CINXE.COM

<!DOCTYPE html> <html class='v2' dir='ltr' lang='en' xmlns='http://www.w3.org/1999/xhtml' xmlns:b='http://www.google.com/2005/gml/b' xmlns:data='http://www.google.com/2005/gml/data' xmlns:expr='http://www.google.com/2005/gml/expr'> <head> <link href='https://www.blogger.com/static/v1/widgets/3566091532-css_bundle_v2.css' rel='stylesheet' type='text/css'/> <meta content='width=1100' name='viewport'/> <meta content='text/html; charset=UTF-8' http-equiv='Content-Type'/> <meta content='blogger' name='generator'/> <link href='https://googleprojectzero.blogspot.com/favicon.ico' rel='icon' type='image/x-icon'/> <link href='https://googleprojectzero.blogspot.com/2017/08/' rel='canonical'/> <link rel="alternate" type="application/atom+xml" title="Project Zero - Atom" href="https://googleprojectzero.blogspot.com/feeds/posts/default" /> <link rel="alternate" type="application/rss+xml" title="Project Zero - RSS" href="https://googleprojectzero.blogspot.com/feeds/posts/default?alt=rss" /> <link rel="service.post" type="application/atom+xml" title="Project Zero - Atom" href="https://www.blogger.com/feeds/4838136820032157985/posts/default" />  <meta content='https://googleprojectzero.blogspot.com/2017/08/' property='og:url'/> <meta content='Project Zero' property='og:title'/> <meta content='News and updates from the Project Zero team at Google' property='og:description'/> <title>Project Zero: August 2017</title> <style type='text/css'>@font-face{font-family:'Open Sans';font-style:normal;font-weight:400;font-stretch:normal;font-display:swap;src:url(//fonts.gstatic.com/s/opensans/v40/memSYaGs126MiZpBA-UvWbX2vVnXBbObj2OVZyOOSr4dVJWUgsjZ0B4gaVY.eot);}</style> <style id='page-skin-1' type='text/css'></style> <style id='template-skin-1' type='text/css'></style> <script type='text/javascript'> (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','https://www.google-analytics.com/analytics.js','ga'); ga('create', 'UA-240546891-1', 'auto', 'blogger'); ga('blogger.send', 'pageview'); </script> <link href='https://www.blogger.com/dyn-css/authorization.css?targetBlogID=4838136820032157985&zx=89189630-7e30-43b5-91d3-8fdab32d43bc' media='none' onload='if(media!='all')media='all'' rel='stylesheet'/><noscript><link href='https://www.blogger.com/dyn-css/authorization.css?targetBlogID=4838136820032157985&zx=89189630-7e30-43b5-91d3-8fdab32d43bc' rel='stylesheet'/></noscript> <meta name='google-adsense-platform-account' content='ca-host-pub-1556223355139109'/> <meta name='google-adsense-platform-domain' content='blogspot.com'/> </head> <body class='loading'> <div class='navbar section' id='navbar' name='Navbar'><div class='widget Navbar' data-version='1' id='Navbar1'><script type="text/javascript"> function setAttributeOnload(object, attribute, val) { if(window.addEventListener) { window.addEventListener('load', function(){ object[attribute] = val; }, false); } else { window.attachEvent('onload', function(){ object[attribute] = val; }); } } </script> <div id="navbar-iframe-container"></div> <script type="text/javascript" src="https://apis.google.com/js/platform.js"></script> <script type="text/javascript"> gapi.load("gapi.iframes:gapi.iframes.style.bubble", function() { if (gapi.iframes && gapi.iframes.getContext) { gapi.iframes.getContext().openChild({ url: 'https://www.blogger.com/navbar.g?targetBlogID\x3d4838136820032157985\x26blogName\x3dProject+Zero\x26publishMode\x3dPUBLISH_MODE_BLOGSPOT\x26navbarType\x3dLIGHT\x26layoutType\x3dLAYOUTS\x26searchRoot\x3dhttps://googleprojectzero.blogspot.com/search\x26blogLocale\x3den\x26v\x3d2\x26homepageUrl\x3dhttps://googleprojectzero.blogspot.com/\x26vt\x3d7568236161501195533', where: document.getElementById("navbar-iframe-container"), id: "navbar-iframe", messageHandlersFilter: gapi.iframes.CROSS_ORIGIN_IFRAMES_FILTER, messageHandlers: { 'blogger-ping': function() {} } }); } }); </script><script type="text/javascript"> (function() { var script = document.createElement('script'); script.type = 'text/javascript'; script.src = '//pagead2.googlesyndication.com/pagead/js/google_top_exp.js'; var head = document.getElementsByTagName('head')[0]; if (head) { head.appendChild(script); }})(); </script> </div></div> <div class='body-fauxcolumns'> <div class='fauxcolumn-outer body-fauxcolumn-outer'> <div class='cap-top'> <div class='cap-left'></div> <div class='cap-right'></div> </div> <div class='fauxborder-left'> <div class='fauxborder-right'></div> <div class='fauxcolumn-inner'> </div> </div> <div class='cap-bottom'> <div class='cap-left'></div> <div class='cap-right'></div> </div> </div> </div> <div class='content'> <div class='content-fauxcolumns'> <div class='fauxcolumn-outer content-fauxcolumn-outer'> <div class='cap-top'> <div class='cap-left'></div> <div class='cap-right'></div> </div> <div class='fauxborder-left'> <div class='fauxborder-right'></div> <div class='fauxcolumn-inner'> </div> </div> <div class='cap-bottom'> <div class='cap-left'></div> <div class='cap-right'></div> </div> </div> </div> <div class='content-outer'> <div class='content-cap-top cap-top'> <div class='cap-left'></div> <div class='cap-right'></div> </div> <div class='fauxborder-left content-fauxborder-left'> <div class='fauxborder-right content-fauxborder-right'></div> <div class='content-inner'> <header> <div class='header-outer'> <div class='header-cap-top cap-top'> <div class='cap-left'></div> <div class='cap-right'></div> </div> <div class='fauxborder-left header-fauxborder-left'> <div class='fauxborder-right header-fauxborder-right'></div> <div class='region-inner header-inner'> <div class='header section' id='header' name='Header'><div class='widget Header' data-version='1' id='Header1'> <div id='header-inner'> <div class='titlewrapper'> <h1 class='title'> <a href='https://googleprojectzero.blogspot.com/'> Project Zero </a> </h1> </div> <div class='descriptionwrapper'> <p class='description'><span>News and updates from the Project Zero team at Google</span></p> </div> </div> </div></div> </div> </div> <div class='header-cap-bottom cap-bottom'> <div class='cap-left'></div> <div class='cap-right'></div> </div> </div> </header> <div class='tabs-outer'> <div class='tabs-cap-top cap-top'> <div class='cap-left'></div> <div class='cap-right'></div> </div> <div class='fauxborder-left tabs-fauxborder-left'> <div class='fauxborder-right tabs-fauxborder-right'></div> <div class='region-inner tabs-inner'> <div class='tabs no-items section' id='crosscol' name='Cross-Column'></div> <div class='tabs no-items section' id='crosscol-overflow' name='Cross-Column 2'></div> </div> </div> <div class='tabs-cap-bottom cap-bottom'> <div class='cap-left'></div> <div class='cap-right'></div> </div> </div> <div class='main-outer'> <div class='main-cap-top cap-top'> <div class='cap-left'></div> <div class='cap-right'></div> </div> <div class='fauxborder-left main-fauxborder-left'> <div class='fauxborder-right main-fauxborder-right'></div> <div class='region-inner main-inner'> <div class='columns fauxcolumns'> <div class='fauxcolumn-outer fauxcolumn-center-outer'> <div class='cap-top'> <div class='cap-left'></div> <div class='cap-right'></div> </div> <div class='fauxborder-left'> <div class='fauxborder-right'></div> <div class='fauxcolumn-inner'> </div> </div> <div class='cap-bottom'> <div class='cap-left'></div> <div class='cap-right'></div> </div> </div> <div class='fauxcolumn-outer fauxcolumn-left-outer'> <div class='cap-top'> <div class='cap-left'></div> <div class='cap-right'></div> </div> <div class='fauxborder-left'> <div class='fauxborder-right'></div> <div class='fauxcolumn-inner'> </div> </div> <div class='cap-bottom'> <div class='cap-left'></div> <div class='cap-right'></div> </div> </div> <div class='fauxcolumn-outer fauxcolumn-right-outer'> <div class='cap-top'> <div class='cap-left'></div> <div class='cap-right'></div> </div> <div class='fauxborder-left'> <div class='fauxborder-right'></div> <div class='fauxcolumn-inner'> </div> </div> <div class='cap-bottom'> <div class='cap-left'></div> <div class='cap-right'></div> </div> </div>  <div class='columns-inner'> <div class='column-center-outer'> <div class='column-center-inner'> <div class='main section' id='main' name='Main'><div class='widget Blog' data-version='1' id='Blog1'> <div class='blog-posts hfeed'> <div class="date-outer"> <h2 class='date-header'><span>Wednesday, August 23, 2017</span></h2> <div class="date-posts"> <div class='post-outer'> <div class='post hentry uncustomized-post-template' itemprop='blogPost' itemscope='itemscope' itemtype='http://schema.org/BlogPosting'> <meta content='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxD2KWaDb3FGJKXg1cc_M_DKFUZyI8IYMeU6xvgD-THRnHNl-5PtCrXyGk2SbKsjVA4K-iN6cj0r54NQ7cNFO7lhnVPg5j23GXCT0Bmn-aR5WOU34Jrr76LVgqoHWG1Zx0DR86s-hNZdE/s600/image8.png' itemprop='image_url'/> <meta content='4838136820032157985' itemprop='blogId'/> <meta content='6142060631914211123' itemprop='postId'/> <a name='6142060631914211123'></a> <h3 class='post-title entry-title' itemprop='name'> <a href='https://googleprojectzero.blogspot.com/2017/08/bypassing-virtualbox-process-hardening.html'>Bypassing VirtualBox Process Hardening on Windows</a> </h3> <div class='post-header'> <div class='post-header-line-1'></div> </div> <div class='post-body entry-content' id='post-body-6142060631914211123' itemprop='description articleBody'> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Posted by James Forshaw, Project Zero</span></div> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br /></span></div> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Processes on Windows are securable objects, which prevents one user logged into a Windows machine from compromising another user’s processes. This is a pretty important security feature, at least from the perspective of a non-administrator user. The security prevents a non-administrator user from compromising the integrity of an arbitrary process. This security barrier breaks down when trying to protect against administrators, specifically administrators with Debug privilege, as enabling this privilege allows the administrator to open any process regardless of the security applied to it.</span></div> <b id="docs-internal-guid-a4f9aa91-0fd8-ca14-3f61-64d8100ed15e" style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">There are cases where applications or the operating system want to actively defend processes from users such as administrators or even, in some cases, the same user as the running process who’d normally have full access. Protecting the processes is a pretty hard challenge if done entirely from user mode applications. Therefore many solutions use kernel support to perform the protection. In the majority of cases these sorts of techniques still have flaws, which we can exploit to compromise the “protected” process.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">This blog post will describe the implementation of Oracle’s VirtualBox protected process and detail three different, but now fixed, ways of bypassing the protection and injecting arbitrary code into the process. The techniques I’ll present can equally be applied to similar implementations of “protected” processes in other applications.</span></div> <h1 dir="ltr" style="line-height: 1.38; margin-bottom: 6pt; margin-top: 20pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 20pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Oracle VirtualBox Process Hardening</span></h1> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Protecting processes entirely in user mode is pretty much impossible, there are just too many ways of injecting content into a process. This is especially true when the process you’re trying to protect is running under the same context as the user you’re trying to block. An attacker could, for example, open a handle to the process with </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">PROCESS_CREATE_THREAD</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> access and directly inject a new thread. Or they could open a thread in the process with </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">THREAD_SET_CONTEXT</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> access and directly change the Instruction Pointer to jump to an arbitrary location. These are just the direct attacks. The attacker could also modify the registry or environment the process is running under, then force the process to load arbitrary COM objects, or </span><a href="https://msdn.microsoft.com/en-us/library/windows/desktop/ms644990(v=vs.85).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Windows Hooks</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. The list of possible modifications is almost endless.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Therefore, VirtualBox (VBOX) enlists the help of the kernel to try to protect its processes. The source code refers to this as Process Hardening. VBOX tries to protect the processes from the same user the process is running under. A detailed rationale and technical overview is provided in </span><a href="https://www.virtualbox.org/browser/vbox/trunk/src/VBox/HostDrivers/Support/SUPR3HardenedMain.cpp?rev=67954#L29" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">source code comments</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. The TL;DR; is the protection gates access to the VBOX kernel drivers, which due to design have a number of methods which can be used to compromise the kernel, or at least elevate privileges. This is why VBOX tries to prevent the current user compromising the process, getting access to the VBOX kernel driver would be a route to Kernel or System privileges. As we’ll see though while some protections also prevent administrators compromising the processes that’s not the aim of the hardening code.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <a href="https://bugs.chromium.org/p/project-zero/issues/detail?id=1091" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Multiple</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> </span><a href="https://bugs.chromium.org/p/project-zero/issues/detail?id=1141" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">examples</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> of issues with the driver and protection from device access were discovered by my colleague Jann in VBOX on Linux. On Linux, VBOX limits access to the VBOX driver to root only, and uses SUID binaries to allow the VBOX user processes to get access to the driver before dropping privileges. On Windows instead of SUID binaries the VBOX driver uses kernel APIs to try to stop users and administrators opening protected processes and injecting code.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The core of the kernel component is in the </span><a href="https://www.virtualbox.org/browser/vbox/trunk/src/VBox/HostDrivers/Support/win/SUPDrv-win.cpp?rev=67954" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Support\win\SUPDrv-win.cpp</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> file. This code registers with two callback mechanisms supported by modern Windows kernels:</span></div> <ol style="margin-bottom: 0pt; margin-top: 0pt;"> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <a href="https://msdn.microsoft.com/en-us/library/windows/hardware/ff559953(v=vs.85).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">PsSetCreateProcessNotifyRoutineEx</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> - Driver is notified when a new process is created.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <a href="https://msdn.microsoft.com/en-us/library/windows/hardware/ff558692(v=vs.85).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">ObRegisterCallback</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> - Driver is notified when Process and Thread handles are created or duplicated.</span></div> </li> </ol> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The notification from </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">PsSetCreateProcessNotifyRoutineEx</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> is used to configure the protection structures for a new process. When the process subsequently tries to open a handle to the VBOX driver the hardening will only permit access after the following verification steps are performed in the call to </span><a href="https://www.virtualbox.org/browser/vbox/trunk/src/VBox/HostDrivers/Support/win/SUPHardenedVerifyProcess-win.cpp?rev=67954#L2420" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">supHardenedWinVerifyProcess</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">:</span></div> <b style="font-weight: normal;"><br /></b> <ol style="margin-bottom: 0pt; margin-top: 0pt;"> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Ensure there are no debuggers attached to the process.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Ensure there is only a single thread in the process, which should be the one opening the driver to prevent in-process races.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Ensure there are no executable memory pages outside of a small set of permitted DLLs.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Verify the signatures of all loaded DLLs.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Check the main executable’s signature and that it is of a permitted type of executable (e.g. VirtualBox.exe).</span></div> </li> </ol> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Signature verification in the kernel is done using custom runtime code compiled into the driver. Only a limited set of Trusted Roots are permitted to be verified at this step, primarily Microsoft’s OS and Authenticode certificates as well as the Oracle certificate that all VBOX binaries are signed with. You can find the list of permitted certificates in the </span><a href="https://www.virtualbox.org/browser/vbox/trunk/src/VBox/HostDrivers/Support/win/Certificates?rev=67954" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">source repository</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">ObRegisterCallback</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> notification is used to limit the maximum access any other user process on the system can be granted to the protected process. The </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">ObRegisterCallback</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> API was designed for </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Anti-Virus</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> to protect processes from being injected into or terminated by malicious code. VBOX uses a similar approach and limits any handle to the protected process to the following access rights:</span></div> <b style="font-weight: normal;"><br /></b> <ul style="margin-bottom: 0pt; margin-top: 0pt;"> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">PROCESS_TERMINATE</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">PROCESS_VM_READ</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">PROCESS_QUERY_INFORMATION</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">PROCESS_QUERY_LIMITED_INFORMATION</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">PROCESS_SUSPEND_RESUME</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">DELETE</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">READ_CONTROL</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">SYNCHRONIZE</span></div> </li> </ul> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The permitted access rights give the user most of the typical rights they’d expect, such as being able to read memory, synchronize to the process and terminate it but does not allow injecting new code into the process. Similarly, access to threads is restricted to the following access rights to prevent modification of a thread’s context or similar attacks.</span></div> <b style="font-weight: normal;"><br /></b> <ul style="margin-bottom: 0pt; margin-top: 0pt;"> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">THREAD_TERMINATE</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">THREAD_GET_CONTEXT</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">THREAD_QUERY_INFORMATION</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">THREAD_QUERY_LIMITED_INFORMATION</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">DELETE</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">READ_CONTROL</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; list-style-type: disc; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">SYNCHRONIZE</span></div> </li> </ul> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">We can verify this access limitation by opening the VirtualBox process and one of its threads and see what access rights we’re granted. For example the following picture highlights the process and thread granted access.</span></div> <a href='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxD2KWaDb3FGJKXg1cc_M_DKFUZyI8IYMeU6xvgD-THRnHNl-5PtCrXyGk2SbKsjVA4K-iN6cj0r54NQ7cNFO7lhnVPg5j23GXCT0Bmn-aR5WOU34Jrr76LVgqoHWG1Zx0DR86s-hNZdE/s841/image8.png' style='display: block; padding: 1em 0; text-align: center;'><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxD2KWaDb3FGJKXg1cc_M_DKFUZyI8IYMeU6xvgD-THRnHNl-5PtCrXyGk2SbKsjVA4K-iN6cj0r54NQ7cNFO7lhnVPg5j23GXCT0Bmn-aR5WOU34Jrr76LVgqoHWG1Zx0DR86s-hNZdE/s600/image8.png" style="max-height: 750; max-width: 600;" /></a> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">While the kernel callbacks prevent direct modification of the process as well as a user trying to compromise the integrity of the process at startup they do very little against runtime DLL injection such as through COM. The hardening implementation needs to decide on what modules it’ll allow to be loaded into the process. The decision, fundamentally, is based on Authenticode code signing.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">There are mitigation options to enable loading only Microsoft signed binaries (such as </span><a href="https://msdn.microsoft.com/en-us/library/windows/desktop/mt706242(v=vs.85).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">PROCESS_MITIGATION_BINARY_SIGNATURE_POLICY</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">). However, this policy isn’t very flexible. Therefore, protected VBOX processes install hooks to a couple of internal functions in user-mode to verify the integrity of any DLL which is being loaded into memory. The hooked functions are:</span></div> <b style="font-weight: normal;"><br /></b> <ol style="margin-bottom: 0pt; margin-top: 0pt;"> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <a href="https://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FExecutable%20Images%2FLdrLoadDll.html" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">LdrLoadDll</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> - Called to load a DLL into memory.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <a href="https://msdn.microsoft.com/en-us/library/windows/hardware/ff566428(v=vs.85).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">NtCreateSection</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> - Called to create an Image Section object for a PE file on disk.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <a href="https://msdn.microsoft.com/en-us/library/dd347461(v=vs.85).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">LdrRegisterDllNotification</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> - This is a quasi-officially supported callback which notifies the application when a new DLL is loaded or unloaded.</span></div> </li> </ol> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">These hooks expand the permitted set of signed DLLs which can be loaded. The kernel signature verification is okay for bootstrapping the process as only Oracle and Microsoft code should be present. However, when it comes to running a non-trivial application ( VirtualBox.exe is certainly non-trivial) you’re likely to need to load third-party signed code such as GPU drivers. As the hooks are in user mode it’s easier to call the system </span><a href="https://msdn.microsoft.com/en-us/library/windows/desktop/aa388208(v=vs.85).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">WinVerifyTrust</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> API which will verify certificate chains using the system certificate stores as well as handling the verification of files signed in a </span><a href="https://docs.microsoft.com/en-us/windows-hardware/drivers/install/catalog-files" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Catalog file</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">If the DLL being loaded doesn’t meet VBOX’s expected criteria for signing then the user-mode hooks will reject loading that DLL. VBOX still doesn't completely trust the user; </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">WinVerifyTrust</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> will chain certificates back to a root certificate in the user’s CA certificates. However, VBOX will only trust system CA certificates. As a non-administrator cannot add a new trusted root certificate to the system’s list of CA certificates this should severely limit the injection of malicious DLLs.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">You can get a real code signing certificate which should also be trusted, but the assumption is malicious code wouldn’t want to go down that route. Even if the code is signed the loader also checks that the DLL file is owned by the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">TrustedInstaller</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> user. This is checked in </span><a href="https://www.virtualbox.org/browser/vbox/trunk/src/VBox/HostDrivers/Support/win/SUPHardenedVerifyImage-win.cpp?rev=67954#L454" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">supHardNtViCheckIsOwnedByTrustedInstallerOrSimilar</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. A normal user should not be able to change the owner of a file to anything but themselves, therefore it should limit the impact of the behavior to allow any signed file to load. </span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The VBOX code does have a function which is supposed to restrict what certificates are permitted </span><a href="https://www.virtualbox.org/browser/vbox/trunk/src/VBox/HostDrivers/Support/win/SUPHardenedVerifyImage-win.cpp?rev=67954#L1901" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">supR3HardenedWinIsDesiredRootCA</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> as roots. In official builds the function’s whitelist of specific CAs is commented out. There’s a blacklist of certificates, however, unless your company is called “</span><a href="https://www.virtualbox.org/browser/vbox/trunk/src/VBox/HostDrivers/Support/win/SUPHardenedVerifyImage-win.cpp?rev=67954#L2016" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">U.S. Robots and Mechanical Men, Inc</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">” the blacklist won’t affect you.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Even with all this protection the process isn’t secure against an administrator. While an administrator can’t bypass the security on opening the process, they can install a local machine Trusted Root CA certificate and sign a DLL, set its owner and force it to be loaded. This will bypass the image verification and load into the verified VBOX process. </span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">In summary the VBOX hardening is attempting to provide the following protections:</span></div> <ol style="margin-bottom: 0pt; margin-top: 0pt;"> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Ensure that no code is injected into protected binaries during initialization.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Prevent user processes from opening “writable” handles to protected processes or threads which would allow arbitrary code injection.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Prevent injection of untrusted DLLs through normal loading routes such as COM.</span></div> </li> </ol> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">This whole process is likely to have some bugs and edge cases. There’s so many different verification checks which must all fit together. So, assuming we don’t want to get a code signing certificate and we don’t have administrator rights how can we get arbitrary code running inside a protected VBOX process? We’ll focus primarily on the third protection in the list, as this is perhaps the most complex part of the protection and therefore is likely to have the most issues.</span></div> <h1 dir="ltr" style="line-height: 1.38; margin-bottom: 6pt; margin-top: 20pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 20pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Exploiting the Chain-of-Trust in COM Registration</span></h1> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The first </span><a href="https://bugs.chromium.org/p/project-zero/issues/detail?id=1103" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">bug</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> I’m going to describe was fixed as CVE-2017-3563 in VBOX version 5.0.38/5.1.20. This issue exploits the chain-of-trust for DLL loading to trick VBOX into loading Microsoft signed DLLs which just happen to allow untrusted arbitrary code execution.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">If you run Process Monitor against the protected VBOX process you’ll notice that it uses COM, specifically it uses the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">VirtualBoxClient</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> class which is implemented in the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">VBoxC.dll</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> COM server.</span></div> <a href='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtrlXa7hCTCigvABNWV7C4N2HWaTmVlTpHHtIlpkADZv_NpN7JPp0b-kz2A2WDAVvKhosVX8nkwzEzTNmsTDggcvhh6apcH4QGcfF6vFnYBiqiBkTS5V9pKGd-ZJ2PpNlWiCIqeWlT0sbWYTcR4lMZsxpNbYT_I4qiXnaEMdQnGoIGbga7awvllfV4/s553/image6.png' style='display: block; padding: 1em 0; text-align: center;'><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtrlXa7hCTCigvABNWV7C4N2HWaTmVlTpHHtIlpkADZv_NpN7JPp0b-kz2A2WDAVvKhosVX8nkwzEzTNmsTDggcvhh6apcH4QGcfF6vFnYBiqiBkTS5V9pKGd-ZJ2PpNlWiCIqeWlT0sbWYTcR4lMZsxpNbYT_I4qiXnaEMdQnGoIGbga7awvllfV4/s553/image6.png" style="max-height: 750; max-width: 600;" /></a> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The nice thing about COM server registration, at least from the perspective of an attacker, is the registration for a COM object can be in one of two places, the user’s registry hive, or the local machine registry hive. For reasons of compatibility the user’s hive is checked first, before falling back to the local machine hive. Therefore it’s possible to override a COM registration with a normal user’s permission, so when an application tries to load the designated COM object the application will instead load whatever DLL we’ve overridden it with.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Hijacking COM objects is not a new technique, it’s been known for many years especially for the purposes of </span><a href="https://attack.mitre.org/wiki/Technique/T1122" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Malware persistence</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. It’s seen a resurgence of late because of the renewed interest in all things COM. However, it’s rare that COM hijacking is of importance for elevation of privilege outside of UAC bypasses. </span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">As an aside, the connection between UAC and COM hijacking is the COM runtime actively tries to prevent the hijack being used as an EoP route by disabling certain User registry lookups if the current process is elevated. Of course it wasn’t always </span><a href="https://www.virusbulletin.com/uploads/pdf/conference_slides/2011/Larimer-VB2011.pdf" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">successful</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. This behavior only makes sense if you view UAC through the prism of it being a defendable security boundary, which Microsoft categorically claim it’s not and never was. For example </span><a href="https://blogs.msdn.microsoft.com/cjacks/2007/02/21/per-user-com-registrations-and-elevated-processes-with-uac-on-windows-vista/" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">this blog post</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> from early 2007 specifically states this behavior is to prevent Elevation of Privilege. I think the COM lookup behavior is one of the clearest indicators that UAC was originally designed to be a security boundary. It failed to meet the security bar and so was famously </span><a href="https://technet.microsoft.com/en-us/library/2007.06.uac.aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">retconned</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> into helping “developers” write better code.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">If we could replace the COM registration with our own code we should be able to get code execution inside the hardened process. In theory all the hardening signing checks should stop us from loading untrusted code. In research, it’s always worth trying something which you believe should fail just in case as sometimes you get a nice surprise. At minimum it’ll give you insight into how the protection really works. I registered a COM object to hijack the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">VirtualBoxClient</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> class in the user’s hive and pointed it at an unsigned DLL (Full Disclosure, I used an admin account to tweak the Owner to </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">TrustedInstaller</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> just to test). When I tried to start a Virtual Machine I got the following dialog.</span></div> <a href='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiILlAZ0ftw7tYAqGSEG8ZNBXOcbAEdcjHVJXy9jDhPIlztURNOPMoT5JTpqjMY39MlNP676PvB7GBW_ehYmiQcGo2l3OnV8kkyaoLyR0ITaQkXBnKADGsjP9pwsWGR5CNzYkxjfzm37f3gUoAIAIqOH8XQ80FqqRob2Ky1LE3NP2sxFo5A7WdWXXlE/s258/image7.png' style='display: block; padding: 1em 0; text-align: center;'><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiILlAZ0ftw7tYAqGSEG8ZNBXOcbAEdcjHVJXy9jDhPIlztURNOPMoT5JTpqjMY39MlNP676PvB7GBW_ehYmiQcGo2l3OnV8kkyaoLyR0ITaQkXBnKADGsjP9pwsWGR5CNzYkxjfzm37f3gUoAIAIqOH8XQ80FqqRob2Ky1LE3NP2sxFo5A7WdWXXlE/s258/image7.png" style="max-height: 750; max-width: 600;" /></a> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">It’s possible that I just made a mistake in the COM registration, however testing the COM object in a separate application worked as expected. Therefore this error is likely a result of failing to load the DLL. Fortunately, VBOX is generous and enables by default a log of all Process Hardening events. It’s named </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">VBoxHardening.log</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> and is located in the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Logs</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> folder in the Virtual Machine you tried to start. Searching for the name of the DLL we find the following entries (heavily modified for brevity):</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supHardenedWinVerifyImageByHandle: -> -22900 (c:\dummy\testdll.dll) </span></div> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supR3HardenedScreenImage/LdrLoadDll: c:\dummy\testdll.dll: Not signed.</span></div> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supR3HardenedMonitor_LdrLoadDll: rejecting 'c:\dummy\testdll.dll'</span></div> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supR3HardenedMonitor_LdrLoadDll: returns rcNt=0xc0000190</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">So clearly our test DLL isn’t signed and so the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">LdrLoadDll</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> hook rejects it. The </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">LdrLoadDll</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> hook returns an error code which propagates back up to the COM DLL loader, which results in COM thinking the class doesn’t exist. </span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">While it’s not surprising that it wasn’t as simple as just specifying our own DLL (and don’t forget we cheated with setting the Owner) it at least gives us hope as this result means the VBOX process will use our hijacked COM registration. All we need therefore is a COM object which meets the following criteria:</span></div> <b style="font-weight: normal;"><br /></b> <ol style="margin-bottom: 0pt; margin-top: 0pt;"> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">It’s signed by a trusted certificate.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">It’s owned by </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">TrustedInstaller.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">When loaded will do something that allows for arbitrary code execution in the process.</span></div> </li> </ol> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Criteria 1 and 2 are easy to meet, any Microsoft COM object on the system is signed by a trusted certificate (one of Microsoft’s publisher certificates) and is almost certainly owned by </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">TrustedInstaller</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. However, criteria 3 would seem much more difficult to meet, a COM object is usually implemented inside the DLL and we can’t modify the DLL itself, otherwise it would no longer be signed. It just so happens that there is a Microsoft signed COM object installed by default which will allow us to meet criteria 3, </span><a href="https://technet.microsoft.com/en-us/library/ee692848.aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Windows Script Components</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> (WSC).</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">WSC, also sometimes called Scriptlets are also having a good run at the moment. They can be used as an </span><a href="http://subt0x10.blogspot.co.uk/2017/04/bypass-application-whitelisting-script.html" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">AppLocker bypass</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> as well as being loaded from HTTP URLs. What’s of most interest in this case is they can also be registered as a COM object. </span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">A registered WSC consists of two parts:</span></div> <ol style="margin-bottom: 0pt; margin-top: 0pt;"> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The WSC runtime </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">scrobj.dll</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> which acts as the in-process COM server.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">A file which contains the implementation of the Scriptlet in a compatible scripting language.</span></div> </li> </ol> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">When an application tries to load the registered class </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">scrobj.dll</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> gets loaded into memory. The COM runtime requests a new object of the required class which causes the WSC runtime to go back to the registry to lookup the URL to the implementation Scriptlet file. The WSC runtime then loads the Scriptlet file and executes the embedded script contained in the file in-process. The key here is that as long as scrobj.dll (and any associated script language libraries such as </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">JScript.dll</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">) are valid signed DLLs from VBOX’s perspective then the script code will run as it can never be checked by the hardening code. This would get arbitrary code running inside the hardened process. First let’s check that scrobj.dll is likely to be allowed to be loaded by VBOX. The following screenshot shows the DLL is both signed by Microsoft and is also owned by </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">TrustedInstaller</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">.</span></div> <a href='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcNQKTxQ76jQ8vC_rqkO-5QfluXXOaYZBL6fi7bPg9-yh8mXZ6OMdgaqHvGV5McW2wkrPxU0C5_cWZuLvjHfvm2JHbBsEr55CFMMecF1ve0hXOm_mfFutxdyb4_isPBajLziLepIHaI-KpHoVu7ZA_zguQUTc4fmg9ubP0chGKA507g9PxXatmswzg/s891/image3.png' style='display: block; padding: 1em 0; text-align: center;'><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcNQKTxQ76jQ8vC_rqkO-5QfluXXOaYZBL6fi7bPg9-yh8mXZ6OMdgaqHvGV5McW2wkrPxU0C5_cWZuLvjHfvm2JHbBsEr55CFMMecF1ve0hXOm_mfFutxdyb4_isPBajLziLepIHaI-KpHoVu7ZA_zguQUTc4fmg9ubP0chGKA507g9PxXatmswzg/s600/image3.png" style="max-height: 750; max-width: 600;" /></a> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">So what does a valid Scriptlet file look like? It’s a simple XML file, I’m not going to go into much detail about what each XML element means, other than to point out the script block which will execute arbitrary JScript code. In this case all this Scriptlet will do when loaded is start the Calculator process. </span></div> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: blue; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><scriptlet></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  </span><span style="background-color: transparent; color: blue; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><registration</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">    </span><span style="background-color: transparent; color: red; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">description</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> =</span><span style="background-color: transparent; color: #8000ff; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">"Component"</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">    </span><span style="background-color: transparent; color: red; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">progid</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">=</span><span style="background-color: transparent; color: #8000ff; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">"Component"</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">    </span><span style="background-color: transparent; color: red; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">version</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">=</span><span style="background-color: transparent; color: #8000ff; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">"1.00"</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">    </span><span style="background-color: transparent; color: red; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">classid</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">=</span><span style="background-color: transparent; color: #8000ff; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">"{DD3FC71D-26C0-4FE1-BF6F-67F633265BBA}"</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  </span><span style="background-color: transparent; color: blue; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">/></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  </span><span style="background-color: transparent; color: blue; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><public/></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  </span><span style="background-color: transparent; color: blue; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><script</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> </span><span style="background-color: transparent; color: red; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">language</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> = </span><span style="background-color: transparent; color: #8000ff; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">"JScript"</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> </span><span style="background-color: transparent; color: blue; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  <![CDATA[</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  </span><span style="background-color: transparent; color: blue; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">new</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> ActiveXObject</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">(</span><span style="background-color: transparent; color: grey; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">'WScript.Shell'</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">).</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Exec</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">(</span><span style="background-color: transparent; color: grey; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">'calc'</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">);</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  ]]></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  </span><span style="background-color: transparent; color: blue; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"></script></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: blue; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"></scriptlet></span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">If you’re written much code in JScript or VBScript you might now notice a problem, these languages can’t do that much unless it’s implemented by a COM object. In the example Scriptlet file we can’t create a new process without loading the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">WScript.Shell</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> COM object and calling its </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Exec</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> method. In order to talk to the VBOX driver, which is whole purpose of injecting code in the first place, we’d need a COM object which gives us that functionality. We can’t implement the code in another COM object as that wouldn’t pass the image signing checks we’re trying to bypass. Of course, there’s always </span><a href="https://bugs.chromium.org/p/project-zero/issues/list?can=1&q=javascript" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">memory corruption bugs</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> in scripting engines but, as everyone already knows by now, I’m not a fan of exploiting memory corruptions so we need some other way of getting fully arbitrary code execution. Time to bring in the big guns, the .NET Framework.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The .NET runtime loads code into memory using the normal DLL loading routines. We can’t therefore load a .NET DLL which isn’t signed into memory as that would still get caught by VBOX’s hardening code. However, .NET does support loading arbitrary code from an in-memory array using the </span><a href="https://msdn.microsoft.com/en-us/library/h538bck7(v=vs.110).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Assembly::Load</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> method and once loaded this code can basically act as if it was native code, calling arbitrary APIs and inspecting/modifying memory. As the .NET framework is signed by Microsoft all we need to do is somehow call the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Load </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">method from our Scriptlet file and we can get full arbitrary code running inside the process. </span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Where do we even start on achieving this goal? From a </span><a href="https://googleprojectzero.blogspot.co.uk/2017/04/exploiting-net-managed-dcom.html" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">previous blog post</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> it’s possible to expose .NET objects as COM objects through registration and by abusing Binary Serialization we can load arbitrary code from a byte array. Many core .NET runtime classes are automatically registered as COM objects which can be loaded and manipulated by a scripting engine. The big question can now be asked, is </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">BinaryFormatter</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> exposed as a COM object? </span></div> <a href='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiWmTsKkrFjQS93_w88f9d8nxiNOwLEb1rakInfdrl0VKyjpUgZRv9AqastueG-OMVbLEudmK0kAsSL4dmJQIFusL996ITMy1eG1zJaygQK27TCKphHALZCSISXkQrFyADR9paDx08yneyR5f5ukjzFv-19X6OgGIlokqkzPKlmqlsmGp1T3H_sATv4/s553/image5.png' style='display: block; padding: 1em 0; text-align: center;'><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiWmTsKkrFjQS93_w88f9d8nxiNOwLEb1rakInfdrl0VKyjpUgZRv9AqastueG-OMVbLEudmK0kAsSL4dmJQIFusL996ITMy1eG1zJaygQK27TCKphHALZCSISXkQrFyADR9paDx08yneyR5f5ukjzFv-19X6OgGIlokqkzPKlmqlsmGp1T3H_sATv4/s553/image5.png" style="max-height: 750; max-width: 600;" /></a> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Why, yes it is. </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">BinaryFormatter</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> is a .NET object that a scripting engine can load and interact with via COM. We could now take the final binary stream from my previous post and execute arbitrary code from memory. In the previous blog post the execution of the untrusted code had to occur during deserialization, in this case we can interact with the results of deserialization in a script which can make the serialization gadgets we need much simpler.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">In the end I chose to deserialize a </span><a href="https://msdn.microsoft.com/en-us/library/system.delegate(v=vs.110).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Delegate</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> object which when executed by the script engine would load an </span><a href="https://msdn.microsoft.com/en-us/library/system.reflection.assembly(v=vs.110).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Assembly</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> from memory and return the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Assembly</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> instance. The script engine could then instantiate an instance of a </span><a href="https://msdn.microsoft.com/en-us/library/system.type(v=vs.110).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Type</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> in that </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Assembly</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> and run arbitrary code. It does sound simple in principle, in reality there are a number of caveats. Rather than bog down this blog post with more detail than necessary the tool I used to generate the Scriptlet file, </span><a href="https://github.com/tyranid/DotNetToJScript" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">DotNetToJScript</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> is available so you can read how it works yourself. Also the PoC is available on the issue tracker </span><a href="https://bugs.chromium.org/p/project-zero/issues/attachment?aid=268607" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">here</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. The chain from the JScript component to being able to call the VBOX driver looks something like the following:</span></div> <a href='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiCZD1hRkYmuyYK7o8quuUIqa0U5r6oAfJ3r_3sTbHU7mqfImdFJLE0nTX_oqDoiSdwcYgMZBovCVtzPmDPCNfj-zXWjtBBlp8SMWncIjSZt8bR7418kV4SYsT_fccd87mzm3jQ3vOPwzqTeaOz92wCW2JBTn-9S65vAmoGHQpV4dSziHued8XoWhAP/s609/image4.png' style='display: block; padding: 1em 0; text-align: center;'><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiCZD1hRkYmuyYK7o8quuUIqa0U5r6oAfJ3r_3sTbHU7mqfImdFJLE0nTX_oqDoiSdwcYgMZBovCVtzPmDPCNfj-zXWjtBBlp8SMWncIjSZt8bR7418kV4SYsT_fccd87mzm3jQ3vOPwzqTeaOz92wCW2JBTn-9S65vAmoGHQpV4dSziHued8XoWhAP/s600/image4.png" style="max-height: 750; max-width: 600;" /></a> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">I’m not going to go into what you can now do with the VBOX driver once you’ve got arbitrary code running the hardened process, that’s certainly a topic for another post. Although you might want to look at one of Jann’s </span><a href="https://bugs.chromium.org/p/project-zero/issues/detail?id=1091" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">issues</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> which describes what you might do on Linux.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">How did Oracle fix the issue? They added a </span><a href="https://www.virtualbox.org/browser/vbox/trunk/src/VBox/HostDrivers/Support/win/SUPHardenedVerifyImage-win.cpp?rev=67954#L146" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">blacklist</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> of DLLs which are not allowed to be loaded by the hardened VBOX process. The only DLL currently in that list is scrobj.dll. The list is checked after the verification of the file has taken place and covers both the current filename as well as the internal </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Original Filename</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> in the version resources. This prevents you just renaming the file to something else, as the version resources are part of the signed PE data and so cannot be modified without invalidating the signature. In fairness to Oracle I’m not sure there was any other sensible way of blocking this attack vector other than a DLL blacklist.</span></div> <h1 dir="ltr" style="line-height: 1.38; margin-bottom: 6pt; margin-top: 20pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 20pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Exploiting User-Mode DLL Loading Behavior </span></h1> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The second </span><a href="https://bugs.chromium.org/p/project-zero/issues/detail?id=1257" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">bug</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> I’m going to describe was fixed as CVE-2017-10204 in VBOX version 5.1.24. This issue exploits the behavior of the Windows DLL loader and some bugs in VBOX to trick the hardening code to allow an unverified DLL to be loaded into memory and executed.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">While this bug doesn’t rely on exploiting COM loading as such, the per-user COM registration is a convenient technique to get </span><a href="https://msdn.microsoft.com/en-us/library/windows/desktop/ms684175(v=vs.85).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">LoadLibrary</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> called with an arbitrary path. Therefore we’ll continue to use the technique of hijacking the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">VirtualBoxClient</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> COM object and just use the in-process server path as a means to load the DLL.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">LoadLibrary</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> is an API with a number of well known, but strange behaviors. One of the more interesting from our perspective is the behavior with filename extensions. Depending on the extension the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">LoadLibrary</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> API might add or remove the extension before trying to load the file. I can summarise it in a table, showing the file name as passed to </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">LoadLibrary</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> and the file it actually tries to load.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="margin-left: 0pt;"> <table style="border-collapse: collapse; border: none; width: 468pt;"><colgroup><col width="*"></col><col width="*"></col></colgroup><tbody> <tr style="height: 0pt;"><td style="background-color: #b7b7b7; border-bottom: solid #000000 1pt; border-left: solid #000000 1pt; border-right: solid #000000 1pt; border-top: solid #000000 1pt; padding: 5pt 5pt 5pt 5pt; vertical-align: top;"><div dir="ltr" style="line-height: 1.2; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Original File Name</span></div> </td><td style="background-color: #b7b7b7; border-bottom: solid #000000 1pt; border-left: solid #000000 1pt; border-right: solid #000000 1pt; border-top: solid #000000 1pt; padding: 5pt 5pt 5pt 5pt; vertical-align: top;"><div dir="ltr" style="line-height: 1.2; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Loaded File Name</span></div> </td></tr> <tr style="height: 0pt;"><td style="border-bottom: solid #000000 1pt; border-left: solid #000000 1pt; border-right: solid #000000 1pt; border-top: solid #000000 1pt; padding: 5pt 5pt 5pt 5pt; vertical-align: top;"><div dir="ltr" style="line-height: 1.2; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">c:\test\abc.dll</span></div> </td><td style="border-bottom: solid #000000 1pt; border-left: solid #000000 1pt; border-right: solid #000000 1pt; border-top: solid #000000 1pt; padding: 5pt 5pt 5pt 5pt; vertical-align: top;"><div dir="ltr" style="line-height: 1.2; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">c:\test\abc.dll</span></div> </td></tr> <tr style="height: 0pt;"><td style="background-color: #93c47d; border-bottom: solid #000000 1pt; border-left: solid #000000 1pt; border-right: solid #000000 1pt; border-top: solid #000000 1pt; padding: 5pt 5pt 5pt 5pt; vertical-align: top;"><div dir="ltr" style="line-height: 1.2; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">c:\test\abc</span></div> </td><td style="background-color: #93c47d; border-bottom: solid #000000 1pt; border-left: solid #000000 1pt; border-right: solid #000000 1pt; border-top: solid #000000 1pt; padding: 5pt 5pt 5pt 5pt; vertical-align: top;"><div dir="ltr" style="line-height: 1.2; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">c:\test\abc.dll</span></div> </td></tr> <tr style="height: 0pt;"><td style="border-bottom: solid #000000 1pt; border-left: solid #000000 1pt; border-right: solid #000000 1pt; border-top: solid #000000 1pt; padding: 5pt 5pt 5pt 5pt; vertical-align: top;"><div dir="ltr" style="line-height: 1.2; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">c:\test\abc.blah</span></div> </td><td style="border-bottom: solid #000000 1pt; border-left: solid #000000 1pt; border-right: solid #000000 1pt; border-top: solid #000000 1pt; padding: 5pt 5pt 5pt 5pt; vertical-align: top;"><div dir="ltr" style="line-height: 1.2; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">c:\test\abc.blah</span></div> </td></tr> <tr style="height: 0pt;"><td style="background-color: #93c47d; border-bottom: solid #000000 1pt; border-left: solid #000000 1pt; border-right: solid #000000 1pt; border-top: solid #000000 1pt; padding: 5pt 5pt 5pt 5pt; vertical-align: top;"><div dir="ltr" style="line-height: 1.2; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">c:\test\abc.</span></div> </td><td style="background-color: #93c47d; border-bottom: solid #000000 1pt; border-left: solid #000000 1pt; border-right: solid #000000 1pt; border-top: solid #000000 1pt; padding: 5pt 5pt 5pt 5pt; vertical-align: top;"><div dir="ltr" style="line-height: 1.2; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">c:\test\abc</span></div> </td></tr> </tbody></table> </div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">I’ve highlighted in green the two important cases. These are the cases where the filename passed into LoadLibrary doesn’t match the filename which eventually gets loaded. The problem for any code trying to verify a DLL file before loading it is </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">CreateFile</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> doesn’t follow these rules so in the highlighted cases if you opened the file for signature verification using the original file name you’d verify a different file to the one which eventually gets loaded.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">In Windows there’s usually a clear separation between Kernel32 code, which tends to deal with the many weird behaviors Win32 has built up over the years and the “clean” NT layer exposed by the kernel through NTDLL. Therefore as LoadLibrary is in Kernel32 and LdrLoadDll (which is the function the hardening hooks) is in NTDLL then this weird extension behavior would be handled in the former. Let’s look at a very simplified version of LoadLibrary to see if that’s the case:</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">HMODULE LoadLibrary</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">(</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">LPCWSTR lpLibFileName</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">)</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">{</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  UNICODE_STRING DllPath</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">;</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  HMODULE ModuleHandle</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">;</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  ULONG Flags </span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">=</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> </span><span style="background-color: transparent; color: green; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">// Flags;</span><span style="background-color: transparent; color: green; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  RtlInitUnicodeString</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">(&</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">DllPath</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">,</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> lpLibFileName</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">);</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  </span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  </span><span style="background-color: transparent; color: blue; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">if</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> </span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">(</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">NT_SUCCESS</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">(</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">LdrLoadDll</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">(</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">DEFAULT_SEARCH_PATH</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">,</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> </span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">      </span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">&</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Flags</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">,</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> </span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">&</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">DllPath</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">,</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> </span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">&</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">ModuleHandle</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">)))</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> </span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">{</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">    </span><span style="background-color: transparent; color: blue; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">return</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> ModuleHandle</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">;</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  </span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">}</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  </span><span style="background-color: transparent; color: blue; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">return</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> </span><span style="background-color: transparent; color: blue; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">NULL</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">;</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">}</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">We can see in this code that for all intents and purposes </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">LoadLibrary</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> is just a wrapper around </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">LdrLoadDll</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. While it’s really more complex than that in reality the takeaway is that </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">LoadLibrary</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> does not modify the path it passes to </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">LdrLoadDll</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> in any way other than converting it to a </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">UNICODE_STRING</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. Therefore perhaps if we specify a DLL to load without an extension VBOX will check the extension-less file for the signature but LdrLoadDll will instead load the file with the .DLL extension.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Before we can test that we’ve got another problem to deal with, the requirement that the file is owned by </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">TrustedInstaller</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. For the file we want VBOX to signature check all we need to do is give an existing valid, signed file a different filename. This is what hard links were created for; we can create a different name in a directory we control which actually links to a system file which is signed and also maintains its original security descriptor including the owner. The trouble with hard links is, as I described almost 2 years ago in a </span><a href="https://googleprojectzero.blogspot.co.uk/2015/12/between-rock-and-hard-link.html" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">blog post</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">, while Windows supports creating links to system files you can’t write to, the Win32 APIs, and by extension the easy to access “</span><a href="https://technet.microsoft.com/en-us/library/cc753194(v=ws.11).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">mklink</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">” command in the CMD shell require the file be opened with </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">FILE_WRITE_ATTRIBUTES</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> access. Instead of using another application to create the link we’ll just copy the file, however the copy will no longer have the original security descriptor and so it’ll no longer be owned by </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">TrustedInstaller</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. To get around that let’s look at the checking code to see if there’s a way around it.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The main check for the Owner is in </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supHardenedWinVerifyImageByLdrMod</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. Almost the first thing that function does is call </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supHardNtViCheckIsOwnedByTrustedInstallerOrSimilar</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> which we saw earlier. However as the comments above the </span><a href="https://www.virtualbox.org/browser/vbox/trunk/src/VBox/HostDrivers/Support/win/SUPHardenedVerifyImage-win.cpp?rev=67954#L1169" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">check indicate</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> the code will also allow files under System32 and WinSxS directories to not be owned by </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">TrustedInstaller</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. This is a bus sized hole in the point of the check, as all we need is one writeable directory under System32. We can find some by running the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Get-AccessibleFile</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> cmdlet in my </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">NtObjectManager </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">PS module.</span></div> <a href='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhrblOYet_yzo5swtK3m9njKiRSnf50HSrPyx0LdY63PuZJQury4ZwzsuZ004V0d1iY264aEfjZjbWvXHll_rfVBUeLaqfhJhXAi7pfWqY-5IcHIQk6rGrRQeOv6ftMJVEIQdAegFDeyeAurQ8uYwjDbWkNR4c_5tH1qQ-VljjMjNfjDyF00WmEpbSH/s891/image1.png' style='display: block; padding: 1em 0; text-align: center;'><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhrblOYet_yzo5swtK3m9njKiRSnf50HSrPyx0LdY63PuZJQury4ZwzsuZ004V0d1iY264aEfjZjbWvXHll_rfVBUeLaqfhJhXAi7pfWqY-5IcHIQk6rGrRQeOv6ftMJVEIQdAegFDeyeAurQ8uYwjDbWkNR4c_5tH1qQ-VljjMjNfjDyF00WmEpbSH/s600/image1.png" style="max-height: 750; max-width: 600;" /></a> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">There are plenty to choose from, we’ll just pick the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Tasks</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> folder as it’s guaranteed to always be there. So the exploit should be as follows:</span></div> <b style="font-weight: normal;"><br /></b> <ol style="margin-bottom: 0pt; margin-top: 0pt;"> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Copy a signed binary to </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">%SystemRoot%\System32\Tasks\Dummy\ABC</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Copy an unsigned binary to </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">%SystemRoot%\System32\Tasks\Dummy\ABC.DLL</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Register a COM hijack pointing the in-process server to the signed file path from 1.</span></div> </li> </ol> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">If you try to start a Virtual Machine you’ll find that this trick works. The hardening code checks the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">ABC</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> file for the signature, but </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">LdrLoadDll</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> ends up loading </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">ABC.DLL</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. Just to check we didn’t just exploit something else let’s check the hardening log:</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">\..\Tasks\dummy\ABC: Owner is not trusted installer</span></div> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">\..\Tasks\dummy\ABC: Relaxing the TrustedInstaller requirement for this DLL (it's in system32).</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supHardenedWinVerifyImageByHandle: -> 0 (\..\Tasks\dummy\ABC)</span></div> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supR3HardenedMonitor_LdrLoadDll: pName=c:\..\tasks\dummy\ABC [calling]</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The first two lines indicate the bypass of the Owner check as we expected. The second two indicate it’s verified the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">ABC</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> file and therefore </span><a href="https://www.virtualbox.org/browser/vbox/trunk/src/VBox/HostDrivers/Support/win/SUPR3HardenedMain-win.cpp?rev=67954#L2044" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">will call the original </span><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">LdrLoadDll</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">, which ultimately will append the extension and try to load </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">ABC.DLL</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> instead. But, wait, how come the other checks in </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">NtCreateSection</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> and the loader callback don’t catch loading a completely different file? Let’s search for any instance of </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">ABC.DLL</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> in the rest of the hardening log to find out:</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">\..\Tasks\dummy\ABC.dll: Owner is not trusted installer </span></div> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">\..\Tasks\dummy\ABC.dll: Relaxing the TrustedInstaller requirement for this DLL (it's in system32).</span></div> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supHardenedWinVerifyImageByHandle: -> 22900 (\..\Tasks\dummy\ABC.dll)</span></div> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supR3HardenedWinVerifyCacheInsert: \..\Tasks\dummy\ABC.dll</span></div> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supR3HardenedDllNotificationCallback:  c:\..\tasks\dummy\ABC.DLL </span></div> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supR3HardenedScreenImage/LdrLoadDll: cache hit (Unknown Status 22900) on \...\Tasks\dummy\ABC.dll</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Again the first two lines indicate we bypassed the Owner check because of our file's location. The next line, </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supHardenedWinVerifyImageByHandle</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> is more interesting however. This function verifies the image file. If you look back in this blog at the earlier log of this check you’ll find it returned the result -22900, which was considered an error. However in this case it’s returning 22900, which as VBOX is treating any result >= 0 as success the hardening code gets confused and assumes that the file is valid. The negative error code is </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">VERR_LDRVI_NOT_SIGNED</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> in the source code, whereas the positive “success” code is </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">VINF_LDRVI_NOT_SIGNED</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. </span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">This seems to be a bug in the verification code when calling code in the </span><a href="https://msdn.microsoft.com/en-us/library/windows/desktop/dn633971(v=vs.85).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">DLL Loader Lock</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">, such as in the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">NtCreateSection</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> hook. The code can’t call </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">WinVerifyTrust</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> in case it tries to load another DLL, which would cause a deadlock. What would normally happen is </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">VINF_LDRVI_NOT_SIGNED</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> is returned from the internal signature checking implementation. That implementation can only handle files with embedded signatures, so if a file isn’t signed it returns that information code to get the verification code to check if the file is catalog signed. What’s supposed to happen is </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">WinVerifyTrust</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> is called and if the file is still not signed it returns the error code, however as WinVerifyTrust can’t be called due to the lock the information code gets propagated to the caller which assumed it’s a success code.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The final question is why the final Loader Callback doesn’t catch the unsigned file? VBOX implements a signed file cache based on the path to avoid checking a file multiple times. When the call to </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supHardenedWinVerifyImageByHandle</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> was taken to be a success the verifier called </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">supR3HardenedWinVerifyCacheInsert</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> to add a cache entry for this path with the “success” code. We can see that in the Loader Callback it tries to verify the file but gets back a “success” code from the cache so assumes everything's okay, and the loading process is allowed to complete.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Quite a complex set of interactions to get code running. How did Oracle fix this issue? They just </span><a href="https://www.virtualbox.org/browser/vbox/trunk/src/VBox/HostDrivers/Support/win/SUPR3HardenedMain-win.cpp?rev=67954#L1913" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">add the DLL extension</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> if there’s no extension present. They also handle the case where the filename has a trailing period (which would be removed when loading the DLL).</span></div> <h1 dir="ltr" style="line-height: 1.38; margin-bottom: 6pt; margin-top: 20pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 20pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Exploiting Kernel-Mode Image Loading Behavior</span></h1> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The final </span><a href="https://bugs.chromium.org/p/project-zero/issues/detail?id=1296" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">bug</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> I’m going to describe was fixed as CVE-2017-10129 in VBOX version 5.1.24. This isn’t really a bug in VBOX as much as it’s an unexpected behavior in Windows. </span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Through all this it’s worth noting that there’s an implicit race condition in what the hardening code is trying to do, specifically if you could change the file between the verification point and the point where the file is mapped. In theory you could do this to VBOX but the timing window is somewhat short. You could use OPLOCKs and the like but it’s a bit of a pain, instead it’d be nice to get the TOCTOU attack for free.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Let’s look at how image files are handled in the kernel. Mapping an image file on Windows is expensive, the OS doesn’t use position independent code and so can’t just map the DLL into memory as a simple file. Instead the DLL must be relocated to a specific memory address. This requires modifying pages of the DLL file to ensure any pointers are correctly fixed up. This is even more important when you bring ASLR into the mix as ASLR will almost always force a DLL to be relocated from its base address. Therefore, Windows caches an instance of an image mapping whenever it can, this is why the load address of a DLL doesn’t change between processes on the same system, it’s using the same cached image section.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The caching is actually in part under control of the filesystem driver. When a file is opened the IO manager will allocate a new instance of the </span><a href="https://msdn.microsoft.com/en-us/library/windows/hardware/ff545834(v=vs.85).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">FILE_OBJECT</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> structure and pass it to the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">IRP_MJ_CREATE</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> handler for the driver. One of the fields that the driver can then initialize is the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">SectionObjectPointer</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. This is an instance of the </span><a href="https://msdn.microsoft.com/en-us/library/windows/hardware/ff563687(v=vs.85).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">SECTION_OBJECT_POINTERS</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> structure, which looks like the following:</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: #8000ff; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">struct</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> SECTION_OBJECT_POINTERS </span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">{</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  PVOID DataSectionObject</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">;</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  PVOID SharedCacheMap</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">;</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">  PVOID ImageSectionObject</span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">;</span><span style="background-color: transparent; color: black; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br class="kix-line-break" /></span><span style="background-color: transparent; color: navy; font-family: 'Courier New'; font-size: 10pt; font-style: normal; font-variant: normal; font-weight: 700; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">};</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The fields themselves are managed by the Cache manager, but the structure itself must be allocated by the File System driver. Specifically the allocation should be one per-file in the filesystem; while each open instance of a specific file will have unique </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">FILE_OBJECT</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> instances the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">SectionObjectPointer</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> should be the same. This allows the Cache manager to fill in the different fields and then reuse them if another instance of the same file tries to be mapped.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The important field here is </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">ImageSectionObject</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> which contains the cached data for the mapped image section. I’m not going to delve into detail of what the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">ImageSectionObject</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> pointer contains as it’s not really relevant. The important thing is if the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">SectionObjectPointer </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">and by extension the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">ImageSectionObject</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> pointers are the same for a </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">FILE_OBJECT</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> instance then mapping that file as an image will map the same cached image mapping. However, as </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">ImageSectionObject</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> pointer is not used when reading from a file it doesn’t follow that what’s actually cached still matches what’s on disk.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Trying to desynchronize the file data from the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">SectionObjectPointer </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">seems to be pretty tricky with an NTFS volume, at least without administrator privileges. One scenario where you can do this desynchronization is via the SMB redirector when accessing network shares. The reason is pretty simple, it’s the local redirector’s responsibility to allocate the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">SectionObjectPointer </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">structure when a file is opened on a remote server. As far as the the redirector’s concerned if it opens the file </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">\Share\File.dll</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> on a server twice then it’s the same file. There’s no real other information the redirector can use to verify the identity of the file, it has to guess. Any property you can think of, </span><a href="https://msdn.microsoft.com/en-us/library/windows/hardware/ff540335(v=vs.85).aspx" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">Object ID</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">, Modification Time can just be a lie. You could easily modify a copy of SAMBA to do this lying for you. The redirector also can’t lock the file and ensure it stays locked. So it seems the redirector just doesn’t bother with any of it, if it looks like the same file from its perspective it assumes it’s fine.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">However this is only for the </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">SectionObjectPointer</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">, if the caller wants to read the contents of the file the SMB redirector will go out to the server and try to read the current state of the file. Again this could all be lies, and the server could return any data it likes. This is how we can create a desynchronization; if we map an image file from a SMB server, change the underlying file data then reopen the file and map the image again the mapped image will be the cached one, but any data read from the file will be what’s current on the server. This way we can map an untrusted DLL first, then replace the file data with a signed, valid file (SMB supports reading the owner of the file, so we can spoof TrustedInstaller), when VBOX tries to load it it will verify the signed file but map the cached untrusted image and it will never know.</span></div> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Having a remote server isn’t ideal, however we can do everything we need by using the local loopback SMB server and access files via the admin shares. Contrary to their names admin shares are not limited to administrators if you’re coming from localhost. The key to getting this to work is to use a Directory Junction. Junctions are resolved on the server, the redirector client knows nothing about them. Therefore as far as the client is concerned if it opens the file \\localhost\c$\Dir\File.dll once, then reopens the same file these could be two completely different files as shown in the following diagram:</span></div> <a href='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEM-azWVXLvonrAYwGzCZh0HmTTm2BKl-MIAV_ZdD-zTBJ1oCezY_OhOd61SC2ZOw0UXKUOHzzqE74iOOUY5d5bJ-0CH4WePujfmAYn1hoBjcCaW8NgIzwGG1gQgC7rGzBzjjQqSoQ_RW7nuBpS0gjXEq0cCVbYQOl8oq6Wa8Byj0WUxu3YP0VZhs9/s1018/image2.png' style='display: block; padding: 1em 0; text-align: center;'><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEM-azWVXLvonrAYwGzCZh0HmTTm2BKl-MIAV_ZdD-zTBJ1oCezY_OhOd61SC2ZOw0UXKUOHzzqE74iOOUY5d5bJ-0CH4WePujfmAYn1hoBjcCaW8NgIzwGG1gQgC7rGzBzjjQqSoQ_RW7nuBpS0gjXEq0cCVbYQOl8oq6Wa8Byj0WUxu3YP0VZhs9/s600/image2.png" style="max-height: 750; max-width: 600;" /></a> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Fortunately, one thing which should be evident from the previous two issues is that VBOX’s hardening code doesn’t really care where the DLL is located as long as it meets its two criteria, it’s owned by </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">TrustedInstaller</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"> and it’s signed. We can point the COM hijack to a SMB share on the local system. Therefore we can perform the attack as follows:</span></div> <b style="font-weight: normal;"><br /></b> <ol style="margin-bottom: 0pt; margin-top: 0pt;"> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Set up a junction on the C: drive pointing at a directory containing our untrusted file.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Map the file via the junction over the c$ admin share using LoadLibrary, do not release the mapping until the exploit is complete.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Change the junction to point to another directory with a valid, signed file with the same name as our untrusted file.</span></div> </li> <li dir="ltr" style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; list-style-type: decimal; text-decoration: none; vertical-align: baseline;"><div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Start VBOX with the COM hijack pointing at the file. VBOX will read the file and verify it’s signed and owned by </span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: italic; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">TrustedInstaller</span><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">, however when it maps it the cached, untrusted image section will be used instead.</span></div> </li> </ol> <b style="font-weight: normal;"><br /></b> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">So how did Oracle fix this? They now check that the mapped file isn’t on a network share by comparing the path against the prefix </span><a href="https://www.virtualbox.org/browser/vbox/trunk/src/VBox/HostDrivers/Support/win/SUPR3HardenedMain-win.cpp?rev=67981#L1644" style="text-decoration: none;"><span style="background-color: transparent; color: #1155cc; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: underline; vertical-align: baseline; white-space: pre-wrap;">\Device\Mup</span></a><span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">. </span></div> <h1 dir="ltr" style="line-height: 1.38; margin-bottom: 6pt; margin-top: 20pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 20pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">Conclusions</span></h1> <br /> <div dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">The implementation of process hardening in VirtualBox is complex and because of that it is quite error prone. I’m sure there are other ways of bypassing the protection, it just requires people to go looking. Of course none of this would be necessary if they didn’t need to protect access to the VirtualBox kernel driver from malicious use, but that’s a design decision that’s probably going to be difficult to fix in the short term.</span></div> <div> <span style="background-color: transparent; color: black; font-family: Arial; font-size: 11pt; font-style: normal; font-variant: normal; font-weight: 400; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;"><br /></span></div> <div style='clear: both;'></div> </div> <div class='post-footer'> <div class='post-footer-line post-footer-line-1'> <span class='post-author vcard'> Posted by <span class='fn' itemprop='author' itemscope='itemscope' itemtype='http://schema.org/Person'> <span itemprop='name'>Anonymous</span> </span> </span> <span class='post-timestamp'> at <meta content='https://googleprojectzero.blogspot.com/2017/08/bypassing-virtualbox-process-hardening.html' itemprop='url'/> <a class='timestamp-link' href='https://googleprojectzero.blogspot.com/2017/08/bypassing-virtualbox-process-hardening.html' rel='bookmark' title='permanent link'><abbr class='published' itemprop='datePublished' title='2017-08-23T09:10:00-07:00'>9:10 AM</abbr></a> </span> <span class='post-comment-link'> <a class='comment-link' href='https://googleprojectzero.blogspot.com/2017/08/bypassing-virtualbox-process-hardening.html#comment-form' onclick=''> No comments: </a> </span> <span class='post-icons'> <span class='item-control blog-admin pid-612473818'> <a href='https://www.blogger.com/post-edit.g?blogID=4838136820032157985&postID=6142060631914211123&from=pencil' title='Edit Post'> <img alt='' class='icon-action' height='18' src='https://resources.blogblog.com/img/icon18_edit_allbkg.gif' width='18'/> </a> </span> </span> <div class='post-share-buttons goog-inline-block'> <a class='goog-inline-block share-button sb-email' href='https://www.blogger.com/share-post.g?blogID=4838136820032157985&postID=6142060631914211123&target=email' target='_blank' title='Email This'><span class='share-button-link-text'>Email This</span></a><a class='goog-inline-block share-button sb-blog' href='https://www.blogger.com/share-post.g?blogID=4838136820032157985&postID=6142060631914211123&target=blog' onclick='window.open(this.href, "_blank", "height=270,width=475"); return false;' target='_blank' title='BlogThis!'><span class='share-button-link-text'>BlogThis!</span></a><a class='goog-inline-block share-button sb-twitter' href='https://www.blogger.com/share-post.g?blogID=4838136820032157985&postID=6142060631914211123&target=twitter' target='_blank' title='Share to X'><span class='share-button-link-text'>Share to X</span></a><a class='goog-inline-block share-button sb-facebook' href='https://www.blogger.com/share-post.g?blogID=4838136820032157985&postID=6142060631914211123&target=facebook' onclick='window.open(this.href, "_blank", "height=430,width=640"); return false;' target='_blank' title='Share to Facebook'><span class='share-button-link-text'>Share to Facebook</span></a><a class='goog-inline-block share-button sb-pinterest' href='https://www.blogger.com/share-post.g?blogID=4838136820032157985&postID=6142060631914211123&target=pinterest' target='_blank' title='Share to Pinterest'><span class='share-button-link-text'>Share to Pinterest</span></a> </div> </div> <div class='post-footer-line post-footer-line-2'> <span class='post-labels'> </span> </div> <div class='post-footer-line post-footer-line-3'> <span class='post-location'> </span> </div> </div> </div> </div> </div></div> </div> <div class='blog-pager' id='blog-pager'> <span id='blog-pager-newer-link'> <a class='blog-pager-newer-link' href='https://googleprojectzero.blogspot.com/search?updated-max=2017-09-28T08:21:00-07:00&max-results=1&reverse-paginate=true' id='Blog1_blog-pager-newer-link' title='Newer Posts'>Newer Posts</a> </span> <span id='blog-pager-older-link'> <a class='blog-pager-older-link' href='https://googleprojectzero.blogspot.com/search?updated-max=2017-08-23T09:10:00-07:00&max-results=1' id='Blog1_blog-pager-older-link' title='Older Posts'>Older Posts</a> </span> <a class='home-link' href='https://googleprojectzero.blogspot.com/'>Home</a> </div> <div class='clear'></div> <div class='blog-feeds'> <div class='feed-links'> Subscribe to: <a class='feed-link' href='https://googleprojectzero.blogspot.com/feeds/posts/default' target='_blank' type='application/atom+xml'>Posts (Atom)</a> </div> </div> </div></div> </div> </div> <div class='column-left-outer'> <div class='column-left-inner'> <aside> </aside> </div> </div> <div class='column-right-outer'> <div class='column-right-inner'> <aside> <div class='sidebar section' id='sidebar-right-1'><div class='widget BlogSearch' data-version='1' id='BlogSearch1'> <h2 class='title'>Search This Blog</h2> <div class='widget-content'> <div id='BlogSearch1_form'> <form action='https://googleprojectzero.blogspot.com/search' class='gsc-search-box' target='_top'> <table cellpadding='0' cellspacing='0' class='gsc-search-box'> <tbody> <tr> <td class='gsc-input'> <input autocomplete='off' class='gsc-input' name='q' size='10' title='search' type='text' value=''/> </td> <td class='gsc-search-button'> <input class='gsc-search-button' title='search' type='submit' value='Search'/> </td> </tr> </tbody> </table> </form> </div> </div> <div class='clear'></div> </div><div class='widget PageList' data-version='1' id='PageList1'> <h2>Pages</h2> <div class='widget-content'> <ul> <li> <a href='https://googleprojectzero.blogspot.com/p/about-project-zero.html'>About Project Zero</a> </li> <li> <a href='https://googleprojectzero.blogspot.com/p/working-at-project-zero.html'>Working at Project Zero</a> </li> <li> <a href='https://googleprojectzero.blogspot.com/p/0day.html'>0day "In the Wild"</a> </li> <li> <a href='https://googleprojectzero.github.io/0days-in-the-wild/rca.html'>0day Exploit Root Cause Analyses</a> </li> <li> <a href='https://googleprojectzero.blogspot.com/p/vulnerability-disclosure-faq.html'>Vulnerability Disclosure FAQ</a> </li> </ul> <div class='clear'></div> </div> </div><div class='widget BlogArchive' data-version='1' id='BlogArchive1'> <h2>Archives</h2> <div class='widget-content'> <div id='ArchiveList'> <div id='BlogArchive1_ArchiveList'> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2024/'> 2024 </a> <span class='post-count' dir='ltr'>(9)</span> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2024/11/'> November </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2024/10/'> October </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2024/06/'> June </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2024/04/'> April </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2023/'> 2023 </a> <span class='post-count' dir='ltr'>(11)</span> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2023/11/'> November </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2023/10/'> October </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2023/09/'> September </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2023/08/'> August </a> <span class='post-count' dir='ltr'>(4)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2023/04/'> April </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2023/03/'> March </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2023/01/'> January </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2022/'> 2022 </a> <span class='post-count' dir='ltr'>(17)</span> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2022/12/'> December </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2022/11/'> November </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2022/10/'> October </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2022/08/'> August </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2022/06/'> June </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2022/05/'> May </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2022/04/'> April </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2022/03/'> March </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2022/02/'> February </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2022/01/'> January </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2021/'> 2021 </a> <span class='post-count' dir='ltr'>(24)</span> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2021/12/'> December </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2021/10/'> October </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2021/09/'> September </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2021/08/'> August </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2021/06/'> June </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2021/05/'> May </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2021/04/'> April </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2021/03/'> March </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2021/02/'> February </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2021/01/'> January </a> <span class='post-count' dir='ltr'>(10)</span> </li> </ul> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2020/'> 2020 </a> <span class='post-count' dir='ltr'>(36)</span> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2020/12/'> December </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2020/11/'> November </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2020/10/'> October </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2020/09/'> September </a> <span class='post-count' dir='ltr'>(4)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2020/08/'> August </a> <span class='post-count' dir='ltr'>(5)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2020/07/'> July </a> <span class='post-count' dir='ltr'>(8)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2020/06/'> June </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2020/04/'> April </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2020/02/'> February </a> <span class='post-count' dir='ltr'>(4)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2020/01/'> January </a> <span class='post-count' dir='ltr'>(5)</span> </li> </ul> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2019/'> 2019 </a> <span class='post-count' dir='ltr'>(27)</span> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2019/12/'> December </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2019/11/'> November </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2019/10/'> October </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2019/09/'> September </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2019/08/'> August </a> <span class='post-count' dir='ltr'>(11)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2019/05/'> May </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2019/04/'> April </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2019/03/'> March </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2019/02/'> February </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2019/01/'> January </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2018/'> 2018 </a> <span class='post-count' dir='ltr'>(22)</span> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2018/12/'> December </a> <span class='post-count' dir='ltr'>(7)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2018/11/'> November </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2018/10/'> October </a> <span class='post-count' dir='ltr'>(4)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2018/09/'> September </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2018/08/'> August </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2018/07/'> July </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2018/06/'> June </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2018/05/'> May </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2018/04/'> April </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2018/01/'> January </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> </li> </ul> <ul class='hierarchy'> <li class='archivedate expanded'> <a class='toggle' href='javascript:void(0)'> <span class='zippy toggle-open'> ▼  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2017/'> 2017 </a> <span class='post-count' dir='ltr'>(19)</span> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2017/12/'> December </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2017/10/'> October </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2017/09/'> September </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate expanded'> <a class='toggle' href='javascript:void(0)'> <span class='zippy toggle-open'> ▼  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2017/08/'> August </a> <span class='post-count' dir='ltr'>(2)</span> <ul class='posts'> <li><a href='https://googleprojectzero.blogspot.com/2017/08/bypassing-virtualbox-process-hardening.html'>Bypassing VirtualBox Process Hardening on Windows</a></li> <li><a href='https://googleprojectzero.blogspot.com/2017/08/windows-exploitation-tricks-arbitrary.html'>Windows Exploitation Tricks: Arbitrary Directory C...</a></li> </ul> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2017/07/'> July </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2017/05/'> May </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2017/04/'> April </a> <span class='post-count' dir='ltr'>(6)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2017/03/'> March </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2017/02/'> February </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2016/'> 2016 </a> <span class='post-count' dir='ltr'>(17)</span> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2016/12/'> December </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2016/11/'> November </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2016/10/'> October </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2016/09/'> September </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2016/08/'> August </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2016/07/'> July </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2016/06/'> June </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2016/03/'> March </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2016/02/'> February </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2016/01/'> January </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2015/'> 2015 </a> <span class='post-count' dir='ltr'>(33)</span> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2015/12/'> December </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2015/11/'> November </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2015/10/'> October </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2015/09/'> September </a> <span class='post-count' dir='ltr'>(4)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2015/08/'> August </a> <span class='post-count' dir='ltr'>(6)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2015/07/'> July </a> <span class='post-count' dir='ltr'>(5)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2015/06/'> June </a> <span class='post-count' dir='ltr'>(4)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2015/05/'> May </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2015/04/'> April </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2015/03/'> March </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2015/02/'> February </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2015/01/'> January </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2014/'> 2014 </a> <span class='post-count' dir='ltr'>(11)</span> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2014/12/'> December </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2014/11/'> November </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2014/10/'> October </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2014/09/'> September </a> <span class='post-count' dir='ltr'>(1)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2014/08/'> August </a> <span class='post-count' dir='ltr'>(2)</span> </li> </ul> <ul class='hierarchy'> <li class='archivedate collapsed'> <a class='toggle' href='javascript:void(0)'> <span class='zippy'> ►  </span> </a> <a class='post-count-link' href='https://googleprojectzero.blogspot.com/2014/07/'> July </a> <span class='post-count' dir='ltr'>(3)</span> </li> </ul> </li> </ul> </div> </div> <script type='text/javascript'> //<![CDATA[ (function(){ let archive_list = document.getElementById('ArchiveList'); if (archive_list == null) return; let cur_year = archive_list.querySelector('.post-count-link').innerText.trim() - 0; let last_year = 2014; let elements = []; const MONTHS = ',Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec'.split(','); let parent = document.getElementById('ArchiveList'); while (parent.childNodes.length) parent.removeChild(parent.childNodes[0]); function fetch_next_year() { let url = 'https://googleprojectzero.blogspot.com/?action=getTitles&widgetId=BlogArchive1&widgetType=BlogArchive&responseType=js&path=https%3A%2F%2Fgoogleprojectzero.blogspot.com%2F'+cur_year; fetch(url).then(resp => { if (!resp.ok) { console.log('http error'); return; } resp.text().then(text => { let scope = { _WidgetManager: { _HandleControllerResult: (name, method, results) => { elements.push(document.createElement('hr')); let year_header = document.createElement('div'); year_header.appendChild(document.createTextNode(cur_year)); year_header.style.fontSize = 'large'; elements.push(year_header); let list = document.createElement('ul'); elements.push(list); for (let obj of results.posts) { let link_parts = obj.url.split('/'); let year = link_parts[3]; let month = link_parts[4]; let el = document.createElement(/*'div'*/'li'); el.style.listStyleType = 'square'; el.style.listStylePosition = 'inside'; let link = document.createElement('a'); el.appendChild(link); link.appendChild(document.createTextNode(obj.title)); link.href = obj.url; let date_trailer = document.createElement('span'); el.appendChild(date_trailer); //date_trailer.appendChild(document.createTextNode(' ('+year+'-'+month+')')); date_trailer.appendChild(document.createTextNode(' ('+MONTHS[parseInt(month, 10)]+')')); //date_trailer.style.textAlign = 'right'; //elements.push(el); list.appendChild(el); } } } }; with (scope) { eval(text); } if (cur_year == last_year) { finish(); } else { cur_year--; fetch_next_year(); } }); }); } fetch_next_year(); function finish() { for (let obj of elements) { parent.appendChild(obj); } console.log(elements); } })(); //]]> </script> <div class='clear'></div> </div> </div></div> <table border='0' cellpadding='0' cellspacing='0' class='section-columns columns-2'> <tbody> <tr> <td class='first columns-cell'> <div class='sidebar no-items section' id='sidebar-right-2-1'></div> </td> <td class='columns-cell'> <div class='sidebar no-items section' id='sidebar-right-2-2'></div> </td> </tr> </tbody> </table> <div class='sidebar no-items section' id='sidebar-right-3'></div> </aside> </div> </div> </div> <div style='clear: both'></div>  </div>  </div> </div> <div class='main-cap-bottom cap-bottom'> <div class='cap-left'></div> <div class='cap-right'></div> </div> </div> <footer> <div class='footer-outer'> <div class='footer-cap-top cap-top'> <div class='cap-left'></div> <div class='cap-right'></div> </div> <div class='fauxborder-left footer-fauxborder-left'> <div class='fauxborder-right footer-fauxborder-right'></div> <div class='region-inner footer-inner'> <div class='foot no-items section' id='footer-1'></div> <table border='0' cellpadding='0' cellspacing='0' class='section-columns columns-2'> <tbody> <tr> <td class='first columns-cell'> <div class='foot no-items section' id='footer-2-1'></div> </td> <td class='columns-cell'> <div class='foot no-items section' id='footer-2-2'></div> </td> </tr> </tbody> </table>  <div class='foot section' id='footer-3' name='Footer'><div class='widget Attribution' data-version='1' id='Attribution1'> <div class='widget-content' style='text-align: center;'> Powered by <a href='https://www.blogger.com' target='_blank'>Blogger</a>. </div> <div class='clear'></div> </div></div> </div> </div> <div class='footer-cap-bottom cap-bottom'> <div class='cap-left'></div> <div class='cap-right'></div> </div> </div> </footer>  </div> </div> <div class='content-cap-bottom cap-bottom'> <div class='cap-left'></div> <div class='cap-right'></div> </div> </div> </div> <script type='text/javascript'> window.setTimeout(function() { document.body.className = document.body.className.replace('loading', ''); }, 10); </script> <script type="text/javascript" src="https://www.blogger.com/static/v1/widgets/984859869-widgets.js"></script> <script type='text/javascript'> window['__wavt'] = 'AOuZoY4GjNjW_Gr_qyaEA8lJ33Abe4c8cw:1732538052953';_WidgetManager._Init('//www.blogger.com/rearrange?blogID\x3d4838136820032157985','//googleprojectzero.blogspot.com/2017/08/','4838136820032157985'); _WidgetManager._SetDataContext([{'name': 'blog', 'data': {'blogId': '4838136820032157985', 'title': 'Project Zero', 'url': 'https://googleprojectzero.blogspot.com/2017/08/', 'canonicalUrl': 'https://googleprojectzero.blogspot.com/2017/08/', 'homepageUrl': 'https://googleprojectzero.blogspot.com/', 'searchUrl': 'https://googleprojectzero.blogspot.com/search', 'canonicalHomepageUrl': 'https://googleprojectzero.blogspot.com/', 'blogspotFaviconUrl': 'https://googleprojectzero.blogspot.com/favicon.ico', 'bloggerUrl': 'https://www.blogger.com', 'hasCustomDomain': false, 'httpsEnabled': true, 'enabledCommentProfileImages': true, 'gPlusViewType': 'FILTERED_POSTMOD', 'adultContent': false, 'analyticsAccountNumber': 'UA-240546891-1', 'encoding': 'UTF-8', 'locale': 'en', 'localeUnderscoreDelimited': 'en', 'languageDirection': 'ltr', 'isPrivate': false, 'isMobile': false, 'isMobileRequest': false, 'mobileClass': '', 'isPrivateBlog': false, 'isDynamicViewsAvailable': true, 'feedLinks': '\x3clink rel\x3d\x22alternate\x22 type\x3d\x22application/atom+xml\x22 title\x3d\x22Project Zero - Atom\x22 href\x3d\x22https://googleprojectzero.blogspot.com/feeds/posts/default\x22 /\x3e\n\x3clink rel\x3d\x22alternate\x22 type\x3d\x22application/rss+xml\x22 title\x3d\x22Project Zero - RSS\x22 href\x3d\x22https://googleprojectzero.blogspot.com/feeds/posts/default?alt\x3drss\x22 /\x3e\n\x3clink rel\x3d\x22service.post\x22 type\x3d\x22application/atom+xml\x22 title\x3d\x22Project Zero - Atom\x22 href\x3d\x22https://www.blogger.com/feeds/4838136820032157985/posts/default\x22 /\x3e\n', 'meTag': '', 'adsenseHostId': 'ca-host-pub-1556223355139109', 'adsenseHasAds': false, 'adsenseAutoAds': false, 'boqCommentIframeForm': true, 'loginRedirectParam': '', 'view': '', 'dynamicViewsCommentsSrc': '//www.blogblog.com/dynamicviews/4224c15c4e7c9321/js/comments.js', 'dynamicViewsScriptSrc': '//www.blogblog.com/dynamicviews/da8f33dd880cc4f1', 'plusOneApiSrc': 'https://apis.google.com/js/platform.js', 'disableGComments': true, 'interstitialAccepted': false, 'sharing': {'platforms': [{'name': 'Get link', 'key': 'link', 'shareMessage': 'Get link', 'target': ''}, {'name': 'Facebook', 'key': 'facebook', 'shareMessage': 'Share to Facebook', 'target': 'facebook'}, {'name': 'BlogThis!', 'key': 'blogThis', 'shareMessage': 'BlogThis!', 'target': 'blog'}, {'name': 'X', 'key': 'twitter', 'shareMessage': 'Share to X', 'target': 'twitter'}, {'name': 'Pinterest', 'key': 'pinterest', 'shareMessage': 'Share to Pinterest', 'target': 'pinterest'}, {'name': 'Email', 'key': 'email', 'shareMessage': 'Email', 'target': 'email'}], 'disableGooglePlus': true, 'googlePlusShareButtonWidth': 0, 'googlePlusBootstrap': '\x3cscript type\x3d\x22text/javascript\x22\x3ewindow.___gcfg \x3d {\x27lang\x27: \x27en\x27};\x3c/script\x3e'}, 'hasCustomJumpLinkMessage': false, 'jumpLinkMessage': 'Read more', 'pageType': 'archive', 'pageName': 'August 2017', 'pageTitle': 'Project Zero: August 2017'}}, {'name': 'features', 'data': {}}, {'name': 'messages', 'data': {'edit': 'Edit', 'linkCopiedToClipboard': 'Link copied to clipboard!', 'ok': 'Ok', 'postLink': 'Post Link'}}, {'name': 'template', 'data': {'name': 'custom', 'localizedName': 'Custom', 'isResponsive': false, 'isAlternateRendering': false, 'isCustom': true}}, {'name': 'view', 'data': {'classic': {'name': 'classic', 'url': '?view\x3dclassic'}, 'flipcard': {'name': 'flipcard', 'url': '?view\x3dflipcard'}, 'magazine': {'name': 'magazine', 'url': '?view\x3dmagazine'}, 'mosaic': {'name': 'mosaic', 'url': '?view\x3dmosaic'}, 'sidebar': {'name': 'sidebar', 'url': '?view\x3dsidebar'}, 'snapshot': {'name': 'snapshot', 'url': '?view\x3dsnapshot'}, 'timeslide': {'name': 'timeslide', 'url': '?view\x3dtimeslide'}, 'isMobile': false, 'title': 'Project Zero', 'description': 'News and updates from the Project Zero team at Google', 'url': 'https://googleprojectzero.blogspot.com/2017/08/', 'type': 'feed', 'isSingleItem': false, 'isMultipleItems': true, 'isError': false, 'isPage': false, 'isPost': false, 'isHomepage': false, 'isArchive': true, 'isLabelSearch': false, 'archive': {'year': 2017, 'month': 8, 'rangeMessage': 'Showing posts from August, 2017'}}}]); _WidgetManager._RegisterWidget('_NavbarView', new _WidgetInfo('Navbar1', 'navbar', document.getElementById('Navbar1'), {}, 'displayModeFull')); _WidgetManager._RegisterWidget('_HeaderView', new _WidgetInfo('Header1', 'header', document.getElementById('Header1'), {}, 'displayModeFull')); _WidgetManager._RegisterWidget('_BlogView', new _WidgetInfo('Blog1', 'main', document.getElementById('Blog1'), {'cmtInteractionsEnabled': false, 'lightboxEnabled': true, 'lightboxModuleUrl': 'https://www.blogger.com/static/v1/jsbin/2646514562-lbx.js', 'lightboxCssUrl': 'https://www.blogger.com/static/v1/v-css/1964470060-lightbox_bundle.css'}, 'displayModeFull')); _WidgetManager._RegisterWidget('_BlogSearchView', new _WidgetInfo('BlogSearch1', 'sidebar-right-1', document.getElementById('BlogSearch1'), {}, 'displayModeFull')); _WidgetManager._RegisterWidget('_PageListView', new _WidgetInfo('PageList1', 'sidebar-right-1', document.getElementById('PageList1'), {'title': 'Pages', 'links': [{'isCurrentPage': false, 'href': 'https://googleprojectzero.blogspot.com/p/about-project-zero.html', 'id': '4384467920505278144', 'title': 'About Project Zero'}, {'isCurrentPage': false, 'href': 'https://googleprojectzero.blogspot.com/p/working-at-project-zero.html', 'id': '2459334498880008057', 'title': 'Working at Project Zero'}, {'isCurrentPage': false, 'href': 'https://googleprojectzero.blogspot.com/p/0day.html', 'id': '3414239791814532209', 'title': '0day \x22In the Wild\x22'}, {'isCurrentPage': false, 'href': 'https://googleprojectzero.github.io/0days-in-the-wild/rca.html', 'title': '0day Exploit Root Cause Analyses'}, {'isCurrentPage': false, 'href': 'https://googleprojectzero.blogspot.com/p/vulnerability-disclosure-faq.html', 'id': '2935252455704572784', 'title': 'Vulnerability Disclosure FAQ'}], 'mobile': false, 'showPlaceholder': true, 'hasCurrentPage': false}, 'displayModeFull')); _WidgetManager._RegisterWidget('_BlogArchiveView', new _WidgetInfo('BlogArchive1', 'sidebar-right-1', document.getElementById('BlogArchive1'), {'languageDirection': 'ltr', 'loadingMessage': 'Loading\x26hellip;'}, 'displayModeFull')); _WidgetManager._RegisterWidget('_AttributionView', new _WidgetInfo('Attribution1', 'footer-3', document.getElementById('Attribution1'), {}, 'displayModeFull')); </script> </body> </html>