CINXE.COM

<!DOCTYPE html> <html lang="en"><head> <meta charset="utf-8" /> <meta http-equiv="X-UA-Compatible" content="IE=edge" /> <meta name="viewport" content="width=device-width, initial-scale=1" /> <meta name="generator" content="Jekyll v3.9.5" /> <meta property="og:title" content="Supply chain threats" /> <meta property="og:locale" content="en_US" /> <meta name="description" content="Attacks can occur at every link in a typical software supply chain, and these kinds of attacks are increasingly public, disruptive, and costly in today’s environment. This page is an introduction to possible attacks throughout the supply chain and how SLSA could help." /> <meta property="og:description" content="Attacks can occur at every link in a typical software supply chain, and these kinds of attacks are increasingly public, disruptive, and costly in today’s environment. This page is an introduction to possible attacks throughout the supply chain and how SLSA could help." /> <meta property="og:site_name" content="SLSA" /> <meta property="og:image" content="/images/icons/android-chrome-192x192.png" /> <meta property="og:type" content="website" /> <meta name="twitter:card" content="summary_large_image" /> <meta property="twitter:image" content="/images/icons/android-chrome-192x192.png" /> <meta property="twitter:title" content="Supply chain threats" /> <script type="application/ld+json"> {"@context":"https://schema.org","@type":"WebPage","description":"Attacks can occur at every link in a typical software supply chain, and these kinds of attacks are increasingly public, disruptive, and costly in today’s environment. This page is an introduction to possible attacks throughout the supply chain and how SLSA could help.","headline":"Supply chain threats","image":"/images/icons/android-chrome-192x192.png","publisher":{"@type":"Organization","logo":{"@type":"ImageObject","url":"/images/icons/android-chrome-512x512.png"}},"url":"/spec/v1.0/threats-overview"}</script>  <link rel="stylesheet" href="/vendor/tailwindcss-2.2.19/tailwind.min.css"> <link rel="stylesheet" href="/assets/main.css"> <link rel="apple-touch-icon" sizes="180x180" href="/images/icons/apple-touch-icon.png"> <link rel="icon" type="image/png" sizes="32x32" href="/images/icons/favicon-32x32.png"> <link rel="icon" type="image/png" sizes="16x16" href="/images/icons/favicon-16x16.png"> <link rel="icon" type="image/png" sizes="16x16" href="/images/icons/favicon-16x16.png"> <link rel="icon" type="image/x-icon" href="/images/icons/favicon.ico"> <link rel="mask-icon" href="/images/icons/safari-pinned-tab.svg" color="#5bbad5"> <meta name="msapplication-TileColor" content="#da532c" /> <meta name="msapplication-square150x150logo" content="/images/icons/mstile-150x150.png" /> <meta name="theme-color" content="#ffffff" /> <title>SLSA • Supply chain threats</title> <link rel="stylesheet" href="/fonts/inter/inter.css"> <link rel="stylesheet" href="/fonts/ibm_plex/IBMPlexMono-Regular.css"> <link rel="stylesheet" href="/fonts/prodigy/ProdigySans.css"> <script src="/vendor/swiper-6.8.4/swiper-bundle.min.js"></script> <link rel="stylesheet" href="/vendor/swiper-6.8.4/swiper-bundle.min.css"> <script defer src="/vendor/alpinejs-3.10.2/cdn.min.js"></script><link type="application/atom+xml" rel="alternate" href="/feed.xml" title="SLSA" /></head> <body x-data="{navOpen: false}" x-init="$refs.body.style.setProperty('--scrollbar-width', `${window.innerWidth - document.body.offsetWidth}px`)" x-ref="body" ><aside class="site-aside flex flex-col flex-none" :class="{'is-open': navOpen}" > <div class="aside-header p-5 flex justify-between items-center show-laptop"> <a rel="author" href="/" class="logo block"> <img class="logo-white" src="/images/logo.svg" alt="SLSA logo" /> </a> <a class="desktop-github-icon" href="https://github.com/slsa-framework/slsa" target="_blank"> <svg width="22" height="22" viewBox="0 0 22 22" fill="currentColor" xmlns="http://www.w3.org/2000/svg"> <path fill-rule="evenodd" clip-rule="evenodd" d="M11.2344 0.150879C5.28641 0.150879 0.468811 4.96848 0.468811 10.9165C0.468811 15.6803 3.55046 19.7039 7.82978 21.1303C8.36806 21.2245 8.56991 20.9016 8.56991 20.619C8.56991 20.3633 8.55646 19.5155 8.55646 18.6139C5.8516 19.1118 5.15184 17.9545 4.93653 17.3489C4.81541 17.0394 4.29059 16.084 3.83306 15.8283C3.45626 15.6264 2.91798 15.1285 3.8196 15.1151C4.66739 15.1016 5.27295 15.8956 5.47481 16.2185C6.44371 17.8468 7.99126 17.3893 8.61028 17.1067C8.70448 16.4069 8.98708 15.9359 9.29659 15.6668C6.90125 15.3977 4.39825 14.4691 4.39825 10.3513C4.39825 9.18051 4.81541 8.21161 5.50172 7.45802C5.39407 7.18888 5.01727 6.08541 5.60938 4.60514C5.60938 4.60514 6.51099 4.32254 8.56991 5.70861C9.43116 5.46639 10.3462 5.34527 11.2613 5.34527C12.1764 5.34527 13.0914 5.46639 13.9527 5.70861C16.0116 4.30909 16.9132 4.60514 16.9132 4.60514C17.5053 6.08541 17.1285 7.18888 17.0209 7.45802C17.7072 8.21161 18.1244 9.16706 18.1244 10.3513C18.1244 14.4826 15.6079 15.3977 13.2126 15.6668C13.6028 16.0032 13.9392 16.6492 13.9392 17.6584C13.9392 19.0983 13.9258 20.2556 13.9258 20.619C13.9258 20.9016 14.1276 21.238 14.6659 21.1303C16.8031 20.4088 18.6602 19.0353 19.9758 17.2031C21.2915 15.3708 21.9994 13.1721 22 10.9165C22 4.96848 17.1824 0.150879 11.2344 0.150879Z" /> </svg> </a> </div> <div class="aside-content px-5 py-1 flex-1 overflow-auto"> <select id="redirectSelect.show-laptop" class="select-dropdown p-1 mx-1 my-4 text-black opacity-80 show-laptop border-gray-400"> <option value="/spec/v1.1/threats-overview" class="inline-block">Version 1.1 RC</option> <option selected value="/spec/v1.0/threats-overview" class="inline-block">Version 1.0</option> <option disabled value="/spec/v0.1/threats-overview" class="inline-block">Version 0.1</option> <option value="/spec/draft/threats-overview" class="inline-block">Working Draft</option> </select> <script> var selectEl = document.getElementById('redirectSelect.show-laptop'); selectEl.onchange = function(){ var goto = this.value; window.location = goto; }; </script> <nav class="site-nav"><ul><li> <a class="nav-link" href="/spec/v1.0/"> Overview </a> </li><li> <span class="section-title">Understanding SLSA</span> <ul><li> <a class="nav-link" href="/spec/v1.0/whats-new"> What's new in v1.0 </a> </li><li> <a class="nav-link" href="/spec/v1.0/about"> About SLSA </a> </li><li> <a class="nav-link is-active" href="/spec/v1.0/threats-overview"> Supply chain threats </a> </li><li> <a class="nav-link" href="/spec/v1.0/use-cases"> Use cases </a> </li><li> <a class="nav-link" href="/spec/v1.0/principles"> Guiding principles </a> </li><li> <a class="nav-link" href="/spec/v1.0/faq"> FAQ </a> </li><li> <a class="nav-link" href="/spec/v1.0/future-directions"> Future directions </a> </li> </ul> </li><li> <span class="section-title">Core specification</span> <ul><li> <a class="nav-link" href="/spec/v1.0/terminology"> Terminology </a> </li><li> <a class="nav-link" href="/spec/v1.0/levels"> Security levels </a> </li><li> <a class="nav-link" href="/spec/v1.0/requirements"> Producing artifacts </a> </li><li> <a class="nav-link" href="/spec/v1.0/distributing-provenance"> Distributing provenance </a> </li><li> <a class="nav-link" href="/spec/v1.0/verifying-artifacts"> Verifying artifacts </a> </li><li> <a class="nav-link" href="/spec/v1.0/verifying-systems"> Verifying build platforms </a> </li><li> <a class="nav-link" href="/spec/v1.0/threats"> Threats & mitigations </a> </li> </ul> </li><li> <span class="section-title">Attestation formats</span> <ul><li> <a class="nav-link" href="/attestation-model"> General model </a> </li><li> <a class="nav-link" href="/spec/v1.0/provenance"> Provenance </a> </li><li> <a class="nav-link" href="/spec/v1.0/verification_summary"> Verification Summary </a> </li> </ul> </li><li> <span class="section-title">How to SLSA</span> <ul><li> <a class="nav-link" href="/get-started"> For developers </a> </li><li> <a class="nav-link" href="/how-to-orgs"> For organizations </a> </li><li> <a class="nav-link" href="/how-to-infra"> For infrastructure providers </a> </li> </ul> </li><li> <a class="nav-link" href="/spec-stages"> Specification stages </a> </li><li> <a class="nav-link" href="/community"> Community </a> </li><li> <a class="nav-link" href="/blog"> Blog </a> </li><li> <a class="nav-link" href="/spec/v1.0/onepage"> Single-page view </a> </li> </ul> </nav> </div> </aside> <div class="site-main"> <header class="site-header flex-none" x-data="{ fixed: false, hidden: false, lastPos: window.scrollY, scrolledPast: false }" x-ref="navbar" x-on:scroll.window=" fixed = window.scrollY > lastPos ? window.scrollY >= $refs.navbar.offsetHeight : window.scrollY > 0; hidden = fixed && window.scrollY > lastPos; if (window.scrollY > $refs.navbar.offsetHeight && !scrolledPast) { setTimeout(() => $refs.navbar.classList.add('is-scrolled-past'), 500); scrolledPast = true; } else if (window.scrollY === 0) { $refs.navbar.classList.remove('is-scrolled-past'); scrolledPast = false; } lastPos = window.scrollY; " x-bind:class="{ 'is-fixed': fixed, 'is-hidden': hidden, 'menu-open': navOpen }" > <div class="site-header-inner h-full flex items-center gap-5" > <button x-on:click="navOpen = !navOpen" :class="{ 'active': navOpen }" class="mobile-menu-button inline-block hide-laptop"> <span></span> <span></span> <span></span> </button> <a rel="author" href="/" class="logo block"> <img class="logo-white" src="/images/logo.svg" alt="SLSA logo" /> </a> <select id="redirectSelect.hide-laptop" class="select-dropdown p-1 mx-1 my-4 text-black opacity-80 hide-laptop border-gray-400"> <option value="/spec/v1.1/threats-overview" class="inline-block">Version 1.1 RC</option> <option selected value="/spec/v1.0/threats-overview" class="inline-block">Version 1.0</option> <option disabled value="/spec/v0.1/threats-overview" class="inline-block">Version 0.1</option> <option value="/spec/draft/threats-overview" class="inline-block">Working Draft</option> </select> <script> var selectEl = document.getElementById('redirectSelect.hide-laptop'); selectEl.onchange = function(){ var goto = this.value; window.location = goto; }; </script> <a class="desktop-github-icon ml-auto" href="https://github.com/slsa-framework/slsa" target="_blank"> <svg width="22" height="22" viewBox="0 0 22 22" fill="currentColor" xmlns="http://www.w3.org/2000/svg"> <path fill-rule="evenodd" clip-rule="evenodd" d="M11.2344 0.150879C5.28641 0.150879 0.468811 4.96848 0.468811 10.9165C0.468811 15.6803 3.55046 19.7039 7.82978 21.1303C8.36806 21.2245 8.56991 20.9016 8.56991 20.619C8.56991 20.3633 8.55646 19.5155 8.55646 18.6139C5.8516 19.1118 5.15184 17.9545 4.93653 17.3489C4.81541 17.0394 4.29059 16.084 3.83306 15.8283C3.45626 15.6264 2.91798 15.1285 3.8196 15.1151C4.66739 15.1016 5.27295 15.8956 5.47481 16.2185C6.44371 17.8468 7.99126 17.3893 8.61028 17.1067C8.70448 16.4069 8.98708 15.9359 9.29659 15.6668C6.90125 15.3977 4.39825 14.4691 4.39825 10.3513C4.39825 9.18051 4.81541 8.21161 5.50172 7.45802C5.39407 7.18888 5.01727 6.08541 5.60938 4.60514C5.60938 4.60514 6.51099 4.32254 8.56991 5.70861C9.43116 5.46639 10.3462 5.34527 11.2613 5.34527C12.1764 5.34527 13.0914 5.46639 13.9527 5.70861C16.0116 4.30909 16.9132 4.60514 16.9132 4.60514C17.5053 6.08541 17.1285 7.18888 17.0209 7.45802C17.7072 8.21161 18.1244 9.16706 18.1244 10.3513C18.1244 14.4826 15.6079 15.3977 13.2126 15.6668C13.6028 16.0032 13.9392 16.6492 13.9392 17.6584C13.9392 19.0983 13.9258 20.2556 13.9258 20.619C13.9258 20.9016 14.1276 21.238 14.6659 21.1303C16.8031 20.4088 18.6602 19.0353 19.9758 17.2031C21.2915 15.3708 21.9994 13.1721 22 10.9165C22 4.96848 17.1824 0.150879 11.2344 0.150879Z" /> </svg> </a> </div> </header> <main class="site-clamp" aria-label="Content"> <header class="content-header"> <h1 class="mb-16">Supply chain threats</h1> </header> <div class="site-content has-toc"> <aside class="table-of-contents flex flex-col"> <div class="rounded-lg p-4 border border-gray-400 mb-4"> Status: <a href="/spec-stages" style="display: inline">Approved</a> </div> <div class="flex-auto rounded-lg p-4 border border-gray-400 overflow-auto"> <p class="header-small uppercase">On this page</p> <ul><li><a href="#summary">Summary</a><ul><li><a href="#real-world-examples">Real-world examples</a></li></ul></li></ul> </div> </aside> <div class="content markdown"> <p>Attacks can occur at every link in a typical software supply chain, and these kinds of attacks are increasingly public, disruptive, and costly in today’s environment.</p> <p>This page is an introduction to possible attacks throughout the supply chain and how SLSA could help. For a more technical discussion, see <a href="/spec/v1.0/threats">Threats & mitigations</a>.</p> <h2 id="summary">Summary</h2> <p><img src="/spec/v1.0/images/supply-chain-threats.svg" alt="Supply Chain Threats" /></p> <p><strong>Note that SLSA does not currently address all of the threats presented here.</strong> See <a href="/spec/v1.0/threats">Threats & mitigations</a> for what is currently addressed and <a href="/spec/v1.0/terminology">Terminology</a> for an explanation of the supply chain model.</p> <p>SLSA’s primary focus is supply chain integrity, with a secondary focus on availability. Integrity means protection against tampering or unauthorized modification at any stage of the software lifecycle. Within SLSA, we divide integrity into source integrity vs build integrity.</p> <p><strong>Source integrity:</strong> Ensure that all changes to the source code reflect the intent of the software producer. Intent of an organization is difficult to define, so SLSA is expected to approximate this as approval from two authorized representatives.</p> <p><strong>Build integrity:</strong> Ensure that the package is built from the correct, unmodified sources and dependencies according to the build recipe defined by the software producer, and that artifacts are not modified as they pass between development stages.</p> <p><strong>Availability:</strong> Ensure that the package can continue to be built and maintained in the future, and that all code and change history is available for investigations and incident response.</p> <h3 id="real-world-examples">Real-world examples</h3> <p>Many recent high-profile attacks were consequences of supply chain integrity vulnerabilities, and could have been prevented by SLSA’s framework. For example:</p> <table> <thead> <tr> <th> <th>Integrity threat <th>Known example <th>How SLSA could help <tbody> <tr> <td>A <td>Submit unauthorized change (to source repo) <td><a href="https://arstechnica.com/information-technology/2021/09/cryptocurrency-launchpad-hit-by-3-million-supply-chain-attack/">SushiSwap</a>: Contractor with repository access pushed a malicious commit redirecting cryptocurrency to themself. <td>Two-person review could have caught the unauthorized change. <tr> <td>B <td>Compromise source repo <td><a href="https://news-web.php.net/php.internals/113838">PHP</a>: Attacker compromised PHP's self-hosted git server and injected two malicious commits. <td>A better-protected source code platform would have been a much harder target for the attackers. <tr> <td>C <td>Build from modified source (not matching source repo) <td><a href="https://www.webmin.com/exploit.html">Webmin</a>: Attacker modified the build infrastructure to use source files not matching source control. <td>A SLSA-compliant build server would have produced provenance identifying the actual sources used, allowing consumers to detect such tampering. <tr> <td>D <td>Use compromised dependency (i.e. A-H, recursively) <td><a href="https://web.archive.org/web/20210909051737/https://schneider.dev/blog/event-stream-vulnerability-explained/">event-stream</a>: Attacker added an innocuous dependency and then later updated the dependency to add malicious behavior. The update did not match the code submitted to GitHub (i.e. attack F). <td>Applying SLSA recursively to all dependencies would have prevented this particular vector, because the provenance would have indicated that it either wasn't built from a proper builder or that the source did not come from GitHub. <tr> <td>E <td>Compromise build process <td><a href="https://www.crowdstrike.com/blog/sunspot-malware-technical-analysis/">SolarWinds</a>: Attacker compromised the build platform and installed an implant that injected malicious behavior during each build. <td>Higher SLSA levels require <a href="requirements#build-requirements">stronger security controls for the build platform</a>, making it more difficult to compromise and gain persistence. <tr> <td>F <td>Upload modified package (not matching build process) <td><a href="https://about.codecov.io/apr-2021-post-mortem/">CodeCov</a>: Attacker used leaked credentials to upload a malicious artifact to a GCS bucket, from which users download directly. <td>Provenance of the artifact in the GCS bucket would have shown that the artifact was not built in the expected manner from the expected source repo. <tr> <td>G <td>Compromise package registry <td><a href="https://theupdateframework.io/papers/attacks-on-package-managers-ccs2008.pdf">Attacks on Package Mirrors</a>: Researcher ran mirrors for several popular package registries, which could have been used to serve malicious packages. <td>Similar to above (F), provenance of the malicious artifacts would have shown that they were not built as expected or from the expected source repo. <tr> <td>H <td>Use compromised package <td><a href="https://blog.sonatype.com/damaging-linux-mac-malware-bundled-within-browserify-npm-brandjack-attempt">Browserify typosquatting</a>: Attacker uploaded a malicious package with a similar name as the original. <td>SLSA does not directly address this threat, but provenance linking back to source control can enable and enhance other solutions. </table> <table> <thead> <tr> <th> <th>Availability threat <th>Known example <th>How SLSA could help <tbody> <tr> <td>D <td>Dependency becomes unavailable <td><a href="https://www.techradar.com/news/this-popular-code-library-is-causing-problems-for-hundreds-of-thousands-of-devs">Mimemagic</a>: Producer intentionally removes package or version of package from repository with no warning. Network errors or service outages may also make packages unavailable temporarily. <td>SLSA does not directly address this threat. </table> <p>A SLSA level helps give consumers confidence that software has not been tampered with and can be securely traced back to source—something that is difficult, if not impossible, to do with most software today.</p> <div class="mt-10 pt-10 border-t flex flex-col sm:flex-row space-between gap-5"> <a href="/spec/v1.0/about" class="border rounded px-4 py-2 text-left">&lsaquo; About SLSA</a> <a href="/spec/v1.0/use-cases" class="sm:ml-auto border rounded px-4 py-2 text-right">Use cases &rsaquo;</a> </div> </div> </div> </main><footer class="site-footer flex-none h-card text-white"> <div class="site-clamp py-4 flex flex-wrap items-start justify-between w-full"> <div class="w-full md:w-1/3 mb-8 md:mb-0"> <p><strong>SLSA is a cross-industry collaboration.</strong><br> © 2024 The Linux Foundation, under the terms of the <a href="https://github.com/slsa-framework/governance">Community Specification License 1.0</a></p> </div> <div class="w-full md:w-1/3 mb-8 md:mb-0"> <p><strong>Privacy statement</strong><br> We use <a href="https://goatcounter.com">GoatCounter</a> to help us improve our website by collecting and reporting information on how it's used. We do not store advertising or tracking cookies. The information we collect does not identify anyone and does not track an individual's use of the site.</p> </div> <div class="w-full md:w-1/4 mb-8 md:mb-0 flex md:justify-end"> <p> <a href="https://github.com/slsa-framework/slsa/blob/089d120f336c9acf4d16af1fd889a26b0d7c372a/docs/spec/v1.0/threats-overview.md?plain=1" target="_blank" class="flex gap-4 h5 font-normal"> View source on GitHub <svg width="22" height="22" viewBox="0 0 22 22" fill="none" xmlns="http://www.w3.org/2000/svg"> <path fill-rule="evenodd" clip-rule="evenodd" d="M11.2344 0.150879C5.28641 0.150879 0.468811 4.96848 0.468811 10.9165C0.468811 15.6803 3.55046 19.7039 7.82978 21.1303C8.36806 21.2245 8.56991 20.9016 8.56991 20.619C8.56991 20.3633 8.55646 19.5155 8.55646 18.6139C5.8516 19.1118 5.15184 17.9545 4.93653 17.3489C4.81541 17.0394 4.29059 16.084 3.83306 15.8283C3.45626 15.6264 2.91798 15.1285 3.8196 15.1151C4.66739 15.1016 5.27295 15.8956 5.47481 16.2185C6.44371 17.8468 7.99126 17.3893 8.61028 17.1067C8.70448 16.4069 8.98708 15.9359 9.29659 15.6668C6.90125 15.3977 4.39825 14.4691 4.39825 10.3513C4.39825 9.18051 4.81541 8.21161 5.50172 7.45802C5.39407 7.18888 5.01727 6.08541 5.60938 4.60514C5.60938 4.60514 6.51099 4.32254 8.56991 5.70861C9.43116 5.46639 10.3462 5.34527 11.2613 5.34527C12.1764 5.34527 13.0914 5.46639 13.9527 5.70861C16.0116 4.30909 16.9132 4.60514 16.9132 4.60514C17.5053 6.08541 17.1285 7.18888 17.0209 7.45802C17.7072 8.21161 18.1244 9.16706 18.1244 10.3513C18.1244 14.4826 15.6079 15.3977 13.2126 15.6668C13.6028 16.0032 13.9392 16.6492 13.9392 17.6584C13.9392 19.0983 13.9258 20.2556 13.9258 20.619C13.9258 20.9016 14.1276 21.238 14.6659 21.1303C16.8031 20.4088 18.6602 19.0353 19.9758 17.2031C21.2915 15.3708 21.9994 13.1721 22 10.9165C22 4.96848 17.1824 0.150879 11.2344 0.150879Z" fill="white"/> </svg> </a> <br> This site is powered by <a href="https://www.netlify.com">Netlify</a> </p> </div> </div> <div class="site-clamp py-4 flex items-start justify-between w-full mb-16 md:mb-0"> <a rel="author" href="/"><img src="/images/logo.svg" alt="SLSA logo" /></a> </div> </footer> </div> </body> </html>