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<span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet 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Click here for more information."><img alt="This is a good article. Click here for more information." src="//upload.wikimedia.org/wikipedia/en/thumb/9/94/Symbol_support_vote.svg/19px-Symbol_support_vote.svg.png" decoding="async" width="19" height="20" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/94/Symbol_support_vote.svg/29px-Symbol_support_vote.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/94/Symbol_support_vote.svg/39px-Symbol_support_vote.svg.png 2x" data-file-width="180" data-file-height="185" /></a></span></div></div> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><p class="mw-empty-elt"> </p> <div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Class of attacks tracking web browser history</div> <p> <b>History sniffing</b> is a class of web vulnerabilities and attacks that allow a website to track a user's <a href="/wiki/Web_browsing_history" title="Web browsing history">web browsing history</a> activities by recording which websites a user has visited and which the user has not. This is done by leveraging long-standing <a href="/wiki/Information_leakage" title="Information leakage">information leakage</a> issues inherent to the design of the web platform, one of the most well-known of which includes detecting <a href="/wiki/CSS" title="CSS">CSS</a> attribute changes in links that the user has already visited. </p><p>Despite being known about since 2002, history sniffing is still considered an unsolved problem. In 2010, researchers revealed that multiple high-profile websites had used history sniffing to identify and track users. Shortly afterwards, <a href="/wiki/Mozilla" title="Mozilla">Mozilla</a> and all other major web browsers implemented defences against history sniffing. However, recent research has shown that these mitigations are ineffective against specific variants of the attack and history sniffing can still occur via visited links and newer browser features. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Background">Background</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=History_sniffing&action=edit&section=1" title="Edit section: Background"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/History_of_the_World_Wide_Web" title="History of the World Wide Web">History of the World Wide Web</a>, <a href="/wiki/Web_security" class="mw-redirect" title="Web security">Web security</a>, and <a href="/wiki/Same-origin_policy" title="Same-origin policy">Same-origin policy</a></div> <p>Early <a href="/wiki/Web_browser" title="Web browser">browsers</a> such as <a href="/wiki/Mosaic_(web_browser)" class="mw-redirect" title="Mosaic (web browser)">Mosaic</a> and <a href="/wiki/Netscape_Navigator" title="Netscape Navigator">Netscape Navigator</a> were built on the model of the web being a set of <a href="/wiki/Static_web_page" title="Static web page">statically</a> linked documents known as pages. In this model, it made sense for the user to know which documents they had previously visited and which they hadn't, regardless of which document was referring to them.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> Mosaic, one of the earliest graphical web browsers, used purple links to show that a page had been visited and blue <a href="/wiki/Hyperlink" title="Hyperlink">links</a> to show pages that had not been visited.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> This paradigm stuck around and was subsequently adopted by all modern web browsers.<sup id="cite_ref-:0_4-0" class="reference"><a href="#cite_note-:0-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p><p>Over the years, the web evolved from its original model of static content towards more dynamic content. In 1995, employees at <a href="/wiki/Netscape" title="Netscape">Netscape</a> added a scripting language, <a href="/wiki/JavaScript" title="JavaScript">Javascript</a>, to its flagship web browser, Netscape Navigator. This addition allowed users to add interactivity to the web page via executing Javascript programs as part of the <a href="/wiki/Rendering_(computer_graphics)" title="Rendering (computer graphics)">rendering process</a>.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> However, this addition came with a new security problem, that of these Javascript programs being able to access each other's <a href="/wiki/Execution_(computing)" title="Execution (computing)">execution context</a> and sensitive information about the user. As a result, shortly afterwards, Netscape Navigator introduced the <a href="/wiki/Same-origin_policy" title="Same-origin policy">same-origin policy</a>. This security measure prevented Javascript from being able to arbitrarily access data in a different web page's execution context.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> However, while the same-origin policy was subsequently extended to cover a large variety of features introduced before its existence, it was never extended to cover hyperlinks since it was perceived to hurt the user's ability to browse the web.<sup id="cite_ref-:0_4-1" class="reference"><a href="#cite_note-:0-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> This innocuous omission would manifest into one of the well known and earliest forms of history sniffing known on the web.<sup id="cite_ref-:1_8-0" class="reference"><a href="#cite_note-:1-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="History">History</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=History_sniffing&action=edit&section=2" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Visited_links_vs_unvisited_links_color_difference.png" class="mw-file-description"><img alt="Text with two links, one titled leukemia is purple, the other is not." src="//upload.wikimedia.org/wikipedia/commons/thumb/2/2a/Visited_links_vs_unvisited_links_color_difference.png/220px-Visited_links_vs_unvisited_links_color_difference.png" decoding="async" width="220" height="126" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/2a/Visited_links_vs_unvisited_links_color_difference.png/330px-Visited_links_vs_unvisited_links_color_difference.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/2a/Visited_links_vs_unvisited_links_color_difference.png/440px-Visited_links_vs_unvisited_links_color_difference.png 2x" data-file-width="590" data-file-height="338" /></a><figcaption>By extracting the colour of certain links, a website can access personally identifiable information. In this example, the website could infer that the user might be interested in <a href="/wiki/Leukemia" title="Leukemia">leukemia</a>, a form of blood cancer.</figcaption></figure> <p>One of the first publicly disclosed reports of a history sniffing exploit was made by Andrew Clover from <a href="/wiki/Purdue_University" title="Purdue University">Purdue University</a> in a mailing list post on <a href="/wiki/Bugtraq" title="Bugtraq">BUGTRAQ</a> in 2002. The post detailed how a malicious website could use Javascript to determine if a given link was of a specific colour, thus revealing if the link had been previously visited.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> While this was initially thought of to be a theoretical exploit with little real-world value, later research by <i>Jang et al.</i> in 2010 revealed that high-profile websites were using this technique in the wild to reveal user browsing data.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> As a result multiple lawsuits were filed against the websites that were found to have used history sniffing alleging a violation of the <a href="/wiki/Computer_Fraud_and_Abuse_Act" title="Computer Fraud and Abuse Act">Computer Fraud and Abuse Act of 1986</a>.<sup id="cite_ref-:1_8-1" class="reference"><a href="#cite_note-:1-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p><p>In the same year, L. David Baron from <a href="/wiki/Mozilla_Corporation" title="Mozilla Corporation">Mozilla Corporation</a> developed a defence against the attack that all major browsers would later adopt. The defence included restrictions against what kinds of <a href="/wiki/CSS" title="CSS">CSS</a> attributes could be used to style visited links. The ability to add background images and CSS transitions to links was disallowed. Additionally, visited links would be treated identically to standard links, with Javascript <a href="/wiki/API" title="API">application programming interfaces</a> (APIs) that allow the website to query the color of specific elements returning the same attributes for a visited link as those for non-visited links. This ensured malicious websites could not simply infer a person's browsing history by querying the colour changes.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> </p><p>In 2011, research by then-<a href="/wiki/Stanford_University" title="Stanford University">Stanford</a> graduate student <a href="/wiki/Jonathan_Mayer" title="Jonathan Mayer">Jonathan Mayer</a> found that advertising company Epic Marketplace Inc. had used history sniffing to collect information about the browsing history of users across the web.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> A subsequent investigation by the <a href="/wiki/Federal_Trade_Commission" title="Federal Trade Commission">Federal Trade Commission</a> (FTC) revealed that Epic Marketplace had used history sniffing code as a part of advertisements in over 24,000 web domains, including <a href="/wiki/ESPN" title="ESPN">ESPN</a> and <a href="/wiki/Papa_John%27s" title="Papa John's">Papa Johns</a>. The Javascript code allowed Epic Marketplace to track if a user has visited any of over 54,000 domains.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-:2_15-0" class="reference"><a href="#cite_note-:2-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> The resulting data was subsequently used by Epic Marketplace to categorize users into specific groups and serve advertisements based on the websites the user had visited. As a result of this investigation, the FTC banned Epic Marketplace Inc. from conducting any form of online advertising and marketing for twenty years and was ordered to permanently delete the data it had collected.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-:2_15-1" class="reference"><a href="#cite_note-:2-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Threat_model">Threat model</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=History_sniffing&action=edit&section=3" title="Edit section: Threat model"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <a href="/wiki/Threat_model" title="Threat model">threat model</a> of history sniffing relies on the adversary being able to direct the victim to a malicious website entirely or partially under the adversary's control. The adversary can accomplish this by compromising a previously good web page, by <a href="/wiki/Phishing" title="Phishing">phishing</a> the user to a web page allowing the adversary to load arbitrary code, or by using a malicious advertisement on an otherwise safe web page.<sup id="cite_ref-:1_8-2" class="reference"><a href="#cite_note-:1-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> While most history sniffing attacks do not require user interactions, specific variants of the attacks need users to interact with particular elements which can often be disguised as buttons, browser games, <a href="/wiki/CAPTCHA" title="CAPTCHA">CAPTCHAs</a>, and other such elements.<sup id="cite_ref-:0_4-2" class="reference"><a href="#cite_note-:0-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Modern_variants">Modern variants</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=History_sniffing&action=edit&section=4" title="Edit section: Modern variants"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Despite being partially mitigated in 2010, history sniffing is still considered an unsolved problem.<sup id="cite_ref-:1_8-3" class="reference"><a href="#cite_note-:1-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> In 2011, researchers at <a href="/wiki/Carnegie_Mellon_University" title="Carnegie Mellon University">Carnegie Mellon University</a> showed that while the defences proposed by Mozilla were sufficient to prevent most non-interactive attacks, such as those found by <i>Jang et al.</i>, they were ineffective against interactive attacks. By showing users overlaid letters, numbers and patterns, which would only reveal themselves if a user had visited a specific website, the researchers were able to trick 307 participants into potentially revealing their browsing history via history sniffing. This was done by presenting the activities in the form of pattern solving problems, chess games and CAPTCHAs.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-:0_4-3" class="reference"><a href="#cite_note-:0-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p><p>In 2018, researchers at the <a href="/wiki/University_of_California,_San_Diego" title="University of California, San Diego">University of California, San Diego</a> demonstrated timing attacks that could bypass the mitigations introduced by Mozilla. By abusing the CSS paint API (which allows developers to draw a background image programmatically) and targeting the <a href="/wiki/Bytecode" title="Bytecode">bytecode</a> <a href="/wiki/Web_cache" title="Web cache">cache</a> of the browser, the researchers were able to time the amount of time it took to paint specific links. Thus, they were able to provide probabilistic techniques for identifying visited websites.<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> </p><p>Since 2019, multiple history sniffing attacks have been found targeting various newer features browsers provide. In 2020, <i>Sanchez-Rola et al.</i> demonstrated that by measuring the time a server takes to respond to a request with <a href="/wiki/HTTP_cookie" title="HTTP cookie">HTTP cookies</a> and then comparing it to how long it took for a server to respond without cookies, a website could perform history sniffing.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> In 2023, <i>Ali et al.</i> demonstrated that newly introduced browser features could be abused also to perform history sniffing. One particularly notable example highlighted was the fact that a recently introduced feature, the Private Tokens API, introduced under Google's <a href="/wiki/Privacy_Sandbox" title="Privacy Sandbox">Privacy Sandbox</a> initiative with an intention to prevent user tracking, could allow malicious actors to exfiltrate users browsing data by using techniques similar to those used for <a href="/wiki/Cross-site_leaks" title="Cross-site leaks">cross-site leak attacks</a>.<sup id="cite_ref-22" class="reference"><a href="#cite_note-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=History_sniffing&action=edit&section=5" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.w3.org/Proposal.html">"WorldWideWeb: Proposal for a HyperText Project"</a>. <i>www.w3.org</i>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20230629071324/https://www.w3.org/Proposal.html">Archived</a> from the original on 29 June 2023<span class="reference-accessdate">. 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Usenix Workshop. 12th 2018. (Woot'18)</i>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:51939166">51939166</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Offensive+Technologies.+Usenix+Workshop.+12th+2018.+%28Woot%2718%29&rft.atitle=Browser+history+%7Bre%3Avisited%7D&rft.date=2018&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A51939166%23id-name%3DS2CID&rft.aulast=Smith&rft.aufirst=Michael&rft.au=Disselkoen%2C+Craig&rft.au=Narayan%2C+Shravan&rft.au=Brown%2C+Fraser&rft.au=Stefan%2C+Deian&rft_id=https%3A%2F%2Fwww.usenix.org%2Fconference%2Fwoot18%2Fpresentation%2Fsmith&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+sniffing" class="Z3988"></span></span> </li> <li id="cite_note-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-21">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSanchez-RolaBalzarottiSantos2020" class="citation journal cs1">Sanchez-Rola, Iskander; Balzarotti, Davide; Santos, Igor (22 December 2020). <a rel="nofollow" class="external text" href="https://doi.org/10.1145%2F3419473">"Cookies from the Past: Timing Server-side Request Processing Code for History Sniffing"</a>. <i>Digital Threats: Research and Practice</i>. <b>1</b> (4): 24:1–24:24. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1145%2F3419473">10.1145/3419473</a></span>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:229716038">229716038</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Digital+Threats%3A+Research+and+Practice&rft.atitle=Cookies+from+the+Past%3A+Timing+Server-side+Request+Processing+Code+for+History+Sniffing&rft.volume=1&rft.issue=4&rft.pages=24%3A1-24%3A24&rft.date=2020-12-22&rft_id=info%3Adoi%2F10.1145%2F3419473&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A229716038%23id-name%3DS2CID&rft.aulast=Sanchez-Rola&rft.aufirst=Iskander&rft.au=Balzarotti%2C+Davide&rft.au=Santos%2C+Igor&rft_id=https%3A%2F%2Fdoi.org%2F10.1145%252F3419473&rfr_id=info%3Asid%2Fen.wikipedia.org%3AHistory+sniffing" class="Z3988"></span></span> </li> <li id="cite_note-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-22">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAliChitaleGhasemisharifKanich2023" class="citation journal cs1">Ali, Mir Masood; Chitale, Binoy; Ghasemisharif, Mohammad; Kanich, Chris; Nikiforakis, Nick; Polakis, Jason (2023). <a rel="nofollow" class="external text" href="https://doi.org/10.14722%2Fndss.2023.24072">"Navigating Murky Waters: Automated Browser Feature Testing for Uncovering Tracking Vectors (ABTUTV)"</a>. <i>Proceedings 2023 Network and Distributed System Security Symposium</i>. Reston, VA: Internet Society. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.14722%2Fndss.2023.24072">10.14722/ndss.2023.24072</a></span>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-891562-83-9" title="Special:BookSources/978-1-891562-83-9"><bdi>978-1-891562-83-9</bdi></a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:257502501">257502501</a>.</cite><span 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<ul><li><a href="/wiki/Computer_security" title="Computer security">Computer security</a></li> <li><a href="/wiki/Automotive_security" title="Automotive security">Automotive security</a></li> <li><a href="/wiki/Cybercrime" title="Cybercrime">Cybercrime</a> <ul><li><a href="/wiki/Cybersex_trafficking" title="Cybersex trafficking">Cybersex trafficking</a></li> <li><a href="/wiki/Computer_fraud" title="Computer fraud">Computer fraud</a></li></ul></li> <li><a href="/wiki/Cybergeddon" title="Cybergeddon">Cybergeddon</a></li> <li><a href="/wiki/Cyberterrorism" title="Cyberterrorism">Cyberterrorism</a></li> <li><a href="/wiki/Cyberwarfare" title="Cyberwarfare">Cyberwarfare</a></li> <li><a href="/wiki/Electromagnetic_warfare" class="mw-redirect" title="Electromagnetic warfare">Electromagnetic warfare</a></li> <li><a href="/wiki/Information_warfare" title="Information warfare">Information warfare</a></li> <li><a href="/wiki/Internet_security" title="Internet security">Internet security</a></li> <li><a href="/wiki/Mobile_security" title="Mobile security">Mobile security</a></li> <li><a href="/wiki/Network_security" title="Network security">Network security</a></li> <li><a href="/wiki/Copy_protection" title="Copy protection">Copy protection</a></li> <li><a href="/wiki/Digital_rights_management" title="Digital rights management">Digital rights management</a></li></ul> </div></td><td class="noviewer navbox-image" rowspan="3" style="width:1px;padding:0 0 0 2px"><div><figure class="mw-halign-center" typeof="mw:File"><a href="/wiki/File:CIAJMK1209-en.svg" class="mw-file-description" title="vectorial version"><img alt="vectorial version" src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c5/CIAJMK1209-en.svg/150px-CIAJMK1209-en.svg.png" decoding="async" width="150" height="150" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c5/CIAJMK1209-en.svg/225px-CIAJMK1209-en.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c5/CIAJMK1209-en.svg/300px-CIAJMK1209-en.svg.png 2x" data-file-width="496" data-file-height="496" /></a><figcaption>vectorial version</figcaption></figure></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Threat_(computer)" class="mw-redirect" title="Threat (computer)">Threats</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Adware" title="Adware">Adware</a></li> <li><a href="/wiki/Advanced_persistent_threat" title="Advanced persistent threat">Advanced persistent threat</a></li> <li><a href="/wiki/Arbitrary_code_execution" title="Arbitrary code execution">Arbitrary code execution</a></li> <li><a href="/wiki/Backdoor_(computing)" title="Backdoor (computing)">Backdoors</a></li> <li>Bombs <ul><li><a href="/wiki/Fork_bomb" title="Fork bomb">Fork</a></li> <li><a href="/wiki/Logic_bomb" title="Logic bomb">Logic</a></li> <li><a href="/wiki/Time_bomb_(software)" title="Time bomb (software)">Time</a></li> <li><a href="/wiki/Zip_bomb" title="Zip bomb">Zip</a></li></ul></li> <li><a href="/wiki/Hardware_backdoor" title="Hardware backdoor">Hardware backdoors</a></li> <li><a href="/wiki/Code_injection" title="Code injection">Code injection</a></li> <li><a href="/wiki/Crimeware" title="Crimeware">Crimeware</a></li> <li><a href="/wiki/Cross-site_scripting" title="Cross-site scripting">Cross-site scripting</a></li> <li><a href="/wiki/Cross-site_leaks" title="Cross-site leaks">Cross-site leaks</a></li> <li><a href="/wiki/DOM_clobbering" title="DOM clobbering">DOM clobbering</a></li> <li><a class="mw-selflink selflink">History sniffing</a></li> <li><a href="/wiki/Cryptojacking" title="Cryptojacking">Cryptojacking</a></li> <li><a href="/wiki/Botnet" title="Botnet">Botnets</a></li> <li><a href="/wiki/Data_breach" title="Data breach">Data breach</a></li> <li><a href="/wiki/Drive-by_download" title="Drive-by download">Drive-by download</a></li> <li><a href="/wiki/Browser_Helper_Object" title="Browser Helper Object">Browser Helper Objects</a></li> <li><a href="/wiki/Computer_virus" title="Computer virus">Viruses</a></li> <li><a href="/wiki/Data_scraping" title="Data scraping">Data scraping</a></li> <li><a href="/wiki/Denial-of-service_attack" title="Denial-of-service attack">Denial-of-service attack</a></li> <li><a href="/wiki/Eavesdropping" title="Eavesdropping">Eavesdropping</a></li> <li><a href="/wiki/Email_fraud" title="Email fraud">Email fraud</a></li> <li><a href="/wiki/Email_spoofing" title="Email spoofing">Email spoofing</a></li> <li><a href="/wiki/Exploit_(computer_security)" title="Exploit (computer security)">Exploits</a></li> <li><a href="/wiki/Dialer#Fraudulent_dialer" title="Dialer">Fraudulent dialers</a></li> <li><a href="/wiki/Hacktivism" title="Hacktivism">Hacktivism</a></li> <li><a href="/wiki/Infostealer" title="Infostealer">Infostealer</a></li> <li><a href="/wiki/Insecure_direct_object_reference" title="Insecure direct object reference">Insecure direct object reference</a></li> <li><a href="/wiki/Keystroke_logging" title="Keystroke logging">Keystroke loggers</a></li> <li><a href="/wiki/Malware" title="Malware">Malware</a></li> <li><a href="/wiki/Payload_(computing)" title="Payload (computing)">Payload</a></li> <li><a href="/wiki/Phishing" title="Phishing">Phishing</a> <ul><li><a href="/wiki/Voice_phishing" title="Voice phishing">Voice</a></li></ul></li> <li><a href="/wiki/Polymorphic_engine" title="Polymorphic engine">Polymorphic engine</a></li> <li><a href="/wiki/Privilege_escalation" title="Privilege escalation">Privilege escalation</a></li> <li><a href="/wiki/Ransomware" title="Ransomware">Ransomware</a></li> <li><a href="/wiki/Rootkit" title="Rootkit">Rootkits</a></li> <li><a href="/wiki/Scareware" title="Scareware">Scareware</a></li> <li><a href="/wiki/Shellcode" title="Shellcode">Shellcode</a></li> <li><a href="/wiki/Spamming" title="Spamming">Spamming</a></li> <li><a href="/wiki/Social_engineering_(security)" title="Social engineering (security)">Social engineering</a></li> <li><a href="/wiki/Spyware" title="Spyware">Spyware</a></li> <li><a href="/wiki/Software_bug" title="Software bug">Software bugs</a></li> <li><a href="/wiki/Trojan_horse_(computing)" title="Trojan horse (computing)">Trojan horses</a></li> <li><a href="/wiki/Hardware_Trojan" title="Hardware Trojan">Hardware Trojans</a></li> <li><a href="/wiki/Remote_access_trojan" class="mw-redirect" title="Remote access trojan">Remote access trojans</a></li> <li><a href="/wiki/Vulnerability_(computing)" class="mw-redirect" title="Vulnerability (computing)">Vulnerability</a></li> <li><a href="/wiki/Web_shell" title="Web shell">Web shells</a></li> <li><a href="/wiki/Wiper_(malware)" title="Wiper (malware)">Wiper</a></li> <li><a href="/wiki/Computer_worm" title="Computer worm">Worms</a></li> <li><a href="/wiki/SQL_injection" title="SQL injection">SQL injection</a></li> <li><a href="/wiki/Rogue_security_software" title="Rogue security software">Rogue security software</a></li> <li><a href="/wiki/Zombie_(computing)" title="Zombie (computing)">Zombie</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Defenses</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Application_security" title="Application security">Application security</a> <ul><li><a href="/wiki/Secure_coding" title="Secure coding">Secure coding</a></li> <li>Secure by default</li> <li><a href="/wiki/Secure_by_design" title="Secure by design">Secure by design</a> <ul><li><a href="/wiki/Misuse_case" title="Misuse case">Misuse case</a></li></ul></li></ul></li> <li><a href="/wiki/Computer_access_control" title="Computer access control">Computer access control</a> <ul><li><a href="/wiki/Authentication" title="Authentication">Authentication</a> 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