{"id":69287,"date":"2026-11-01T19:34:00","date_gmt":"2026-11-01T14:04:00","guid":{"rendered":"https:\/\/www.quickonlinetips.com\/archives\/?p=69287"},"modified":"2026-11-01T16:51:46","modified_gmt":"2026-11-01T11:21:46","slug":"are-vs-code-extensions-safe","status":"publish","type":"post","link":"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/","title":{"rendered":"Are VS Code and Cursor Extensions Safe? How to Check an Extension Is Genuine Before You Install It"},"content":{"rendered":"<p>Are VS Code extensions safe? Most are, but an extension runs with the same access to your files, terminal and keys as you do, so one fake or tampered extension can steal secrets or open a backdoor. This guide gives you a practical checklist to check that a VS Code or Cursor extension is genuine before you install it, the settings that protect you from bad updates, and what to do if you think you installed a fake.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.quickonlinetips.com\/archives\/wp-content\/uploads\/check-vs-code-extension-genuine-puzzle-piece.jpg\" alt=\"A single orange puzzle piece on a pile of grey pieces, like spotting the odd extension out\" width=\"1200\" height=\"630\" \/><\/p>\n<blockquote><p><strong>Quick answer:<\/strong> Before installing, check the exact extension ID and publisher, the verified badge, the install count and history, the linked homepage and source repository, and recent reviews. Install only from the official marketplace link on the developer&#8217;s own website. Then reduce risk from future updates: turn off auto-update for powerful extensions, use an install cooldown in Cursor, and keep only extensions you actually use. No single check is perfect, because a tampered update can arrive under a genuine publisher&#8217;s name.<\/p><\/blockquote>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_89 counter-hierarchy ez-toc-counter ez-toc-custom ez-toc-container-direction\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<label for=\"ez-toc-cssicon-toggle-item-6ae767fc657e4\" class=\"ez-toc-cssicon-toggle-label\"><span class=\"ez-toc-cssicon\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #1a202c;color:#1a202c\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #1a202c;color:#1a202c\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/label><input type=\"checkbox\"  id=\"ez-toc-cssicon-toggle-item-6ae767fc657e4\" checked aria-label=\"Toggle\" \/><nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/#Why_extensions_are_a_security_risk\" >Why extensions are a security risk<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/#10-step_checklist_is_this_extension_genuine\" >10-step checklist: is this extension genuine?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/#Settings_that_protect_you_from_bad_updates\" >Settings that protect you from bad updates<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/#In_VS_Code\" >In VS Code<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/#In_Cursor\" >In Cursor<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/#Good_habits_for_every_developer\" >Good habits for every developer<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/#Think_you_installed_a_fake_extension_Do_this\" >Think you installed a fake extension? Do this<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/#What_changed_in_2026_a_tampered_Claude_Code_extension_in_Cursor\" >What changed in 2026: a tampered Claude Code extension in Cursor<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/#FAQ\" >FAQ<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/#Are_VS_Code_extensions_safe\" >Are VS Code extensions safe?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/#Can_Cursor_use_VS_Code_extensions\" >Can Cursor use VS Code extensions?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/#What_is_Open_VSX\" >What is Open VSX?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/11\/are-vs-code-extensions-safe\/#How_do_I_report_a_malicious_extension\" >How do I report a malicious extension?<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"Why_extensions_are_a_security_risk\"><\/span>Why extensions are a security risk<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>VS Code extensions are small programs, not just themes. Microsoft&#8217;s own documentation notes that extensions run with the same permissions as VS Code itself, so they can read and write files, run commands and make network requests. AI coding extensions are especially attractive to attackers because developers install them quickly and often give them access to API keys, cloud credentials and source code.<\/p>\n<p>There are also two main stores. VS Code uses the <a href=\"https:\/\/marketplace.visualstudio.com\/vscode\" target=\"_blank\" rel=\"noopener\">Visual Studio Marketplace<\/a>. Cursor and several other VS Code-based editors use extensions from the open <a href=\"https:\/\/open-vsx.org\/\" target=\"_blank\" rel=\"noopener\">Open VSX<\/a> registry through their own marketplace. The same extension name can therefore exist in more than one store, and each store has its own checks.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"10-step_checklist_is_this_extension_genuine\"><\/span>10-step checklist: is this extension genuine?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<ol>\n<li><strong>Start from the developer&#8217;s website.<\/strong> Go to the tool&#8217;s official site or documentation and use their install link. Don&#8217;t search the marketplace for a popular name and click the first result.<\/li>\n<li><strong>Check the exact extension ID.<\/strong> Every extension has an ID in the form <code>publisher.extension-name<\/code>, shown on its marketplace page. Compare it letter by letter with the ID in the official docs; fake copies often use a look-alike publisher name with an extra letter, hyphen or swapped character.<\/li>\n<li><strong>Look for the verified publisher badge.<\/strong> In VS Code, a blue check mark next to the publisher&#8217;s name means the publisher has proved it owns the domain shown, and Microsoft says the Marketplace has verified that domain and the publisher&#8217;s good standing for at least six months (<a href=\"https:\/\/code.visualstudio.com\/docs\/configure\/extensions\/extension-runtime-security\" target=\"_blank\" rel=\"noopener\">VS Code docs<\/a>). Cursor also has a publisher verification badge for Open VSX listings (<a href=\"https:\/\/cursor.com\/docs\/configuration\/extensions\" target=\"_blank\" rel=\"noopener\">Cursor docs<\/a>). Treat the badge as one signal, not proof.<\/li>\n<li><strong>Compare install counts and history.<\/strong> A copy of a famous extension with a few hundred installs, a brand-new listing date, or a sudden jump in version number is a warning sign.<\/li>\n<li><strong>Open the repository link.<\/strong> Genuine extensions usually link to a public source repository or official site. Check that the repo belongs to the real company and that its latest release matches the marketplace version.<\/li>\n<li><strong>Read the latest reviews and issues.<\/strong> Sort reviews by newest and skim the repo&#8217;s issue tracker for reports of strange behaviour after an update.<\/li>\n<li><strong>Check the changelog.<\/strong> A new version with no release notes, or one published at an odd time without any announcement from the developer, deserves a short wait.<\/li>\n<li><strong>Look at what it asks for.<\/strong> Be careful with extensions that want you to paste tokens, run setup scripts, or install extra binaries from unofficial links.<\/li>\n<li><strong>Avoid random VSIX files.<\/strong> A <code>.vsix<\/code> file shared in a chat, forum or email skips the marketplace&#8217;s malware scanning. Only install a VSIX from the developer&#8217;s own release page.<\/li>\n<li><strong>Search the name plus &#8220;malicious&#8221;.<\/strong> A quick web search for the extension name with &#8220;malicious&#8221; or &#8220;fake&#8221; often shows warnings from security researchers within hours.<\/li>\n<\/ol>\n<h2><span class=\"ez-toc-section\" id=\"Settings_that_protect_you_from_bad_updates\"><\/span>Settings that protect you from bad updates<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The hardest attack to spot is a tampered update to a genuine extension, because the publisher and ID look correct. These settings limit the damage.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"In_VS_Code\"><\/span>In VS Code<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li><strong>Publisher trust prompt:<\/strong> since VS Code 1.97, installing an extension from a new third-party publisher asks you to confirm you trust that publisher. Read the prompt; don&#8217;t click through. You can review the list with the command <strong>Extensions: Manage Trusted Extensions Publishers<\/strong>.<\/li>\n<li><strong>Turn off auto-update for powerful extensions:<\/strong> right-click an extension in the Extensions view and turn off auto update, or set <code>extensions.autoUpdate<\/code> in Settings. Update manually after the release has been out for a day or two.<\/li>\n<li><strong>Use Workspace Trust:<\/strong> open unfamiliar projects in Restricted Mode so their tasks and settings can&#8217;t run code automatically.<\/li>\n<li><strong>Allow-list extensions at work:<\/strong> VS Code lets organisations restrict which extensions can be installed; ask your IT team about it.<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"In_Cursor\"><\/span>In Cursor<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li><strong>Install cooldown:<\/strong> Cursor&#8217;s <code>extensions.installCooldownHours<\/code> setting delays installs and updates until a marketplace version has been public for the number of hours you choose. Team admins can enforce it for everyone with <strong>Marketplace Install Cooldown (hours)<\/strong> in team settings. Cursor&#8217;s docs say the default is 0 (off), so set a value such as 24 or 48.<\/li>\n<li><strong>Allowed extensions for teams:<\/strong> admins can restrict installs to approved publishers or extension IDs with the <code>AllowedExtensions<\/code> setting, and enterprise teams can require extension signature verification.<\/li>\n<\/ul>\n<p>A cooldown is one of the simplest protections against short-lived malicious uploads, because most are found and removed within hours.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Good_habits_for_every_developer\"><\/span>Good habits for every developer<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<ul>\n<li>Keep your extension list short and remove anything you haven&#8217;t used in months.<\/li>\n<li>Store API keys in a password manager or secret store, not in plain-text files in your home folder. Our comparison of <a href=\"https:\/\/www.quickonlinetips.com\/archives\/2026\/10\/best-free-password-manager\/\">free password managers<\/a> covers good options.<\/li>\n<li>Use separate, limited API keys for AI coding tools, so a leak can be revoked without breaking everything else.<\/li>\n<li>Keep your editor and operating system updated, and use an endpoint security tool on work machines.<\/li>\n<\/ul>\n<h2><span class=\"ez-toc-section\" id=\"Think_you_installed_a_fake_extension_Do_this\"><\/span>Think you installed a fake extension? Do this<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<ol>\n<li><strong>Disconnect and preserve evidence<\/strong> if it is a work machine, and tell your security team.<\/li>\n<li><strong>Uninstall the extension<\/strong>, but don&#8217;t stop there: malware may have added persistence that survives removal.<\/li>\n<li><strong>Check for added SSH keys<\/strong> in <code>~\/.ssh\/authorized_keys<\/code> and remove any key you don&#8217;t recognise.<\/li>\n<li><strong>Look for new startup items<\/strong>: LaunchAgents on macOS, crontab entries on Linux, scheduled tasks and Startup folder items on Windows.<\/li>\n<li><strong>Rotate secrets<\/strong>: API keys, cloud credentials, Git tokens and SSH keys that were on the machine.<\/li>\n<li><strong>Follow the vendor&#8217;s advisory<\/strong> for exact indicators and removal steps, and rebuild the machine if you can&#8217;t be sure it is clean.<\/li>\n<\/ol>\n<h2><span class=\"ez-toc-section\" id=\"What_changed_in_2026_a_tampered_Claude_Code_extension_in_Cursor\"><\/span>What changed in 2026: a tampered Claude Code extension in Cursor<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><em>Updated 1 November 2026.<\/em><\/p>\n<p>On 29 October 2026, a tampered copy of Anthropic&#8217;s Claude Code extension (versions 2.1.312 and 2.1.313, under the genuine ID <code>anthropic.claude-code<\/code>) was available in Cursor&#8217;s extension marketplace for about 11 hours. Anthropic said it did not build or publish that copy and that its own systems were not compromised. According to <a href=\"https:\/\/www.microsoft.com\/en-us\/security\/blog\/2026\/10\/30\/inside-malicious-claude-code-branded-cursor-extension-persistent-ssh-backdoor\/\" target=\"_blank\" rel=\"noopener\">Microsoft Threat Intelligence<\/a>, the injected code tried to add an attacker&#8217;s SSH key, open a reverse SSH tunnel, set up persistence and send host details to the attacker; Microsoft says the package never appeared on the Visual Studio Marketplace or npm. <a href=\"https:\/\/www.sophos.com\/en-us\/blog\/malicious-claude-code-extension-distributed-through-cursor-marketplace\" target=\"_blank\" rel=\"noopener\">Sophos<\/a> reported Cursor&#8217;s estimate of up to 5,000 affected users. Cursor removed the version and published removal guidance.<\/p>\n<p>The lesson for everyone: checking the publisher name would not have caught this one, because the ID was genuine. An install cooldown, careful updates and quick secret rotation are what limit the damage.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"FAQ\"><\/span>FAQ<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h3><span class=\"ez-toc-section\" id=\"Are_VS_Code_extensions_safe\"><\/span>Are VS Code extensions safe?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Most popular extensions from verified publishers are safe, and the Visual Studio Marketplace scans every new extension and update for malware. But extensions have broad access to your computer, so install only what you need and check each one.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Can_Cursor_use_VS_Code_extensions\"><\/span>Can Cursor use VS Code extensions?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Yes. Cursor is based on VS Code and installs extensions from the Open VSX registry through its own marketplace, so most VS Code extensions are available, sometimes in builds maintained by Cursor.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"What_is_Open_VSX\"><\/span>What is Open VSX?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Open VSX is an open-source extension registry run by the Eclipse Foundation. Editors that can&#8217;t use Microsoft&#8217;s marketplace, such as Cursor and VSCodium, get extensions from it.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"How_do_I_report_a_malicious_extension\"><\/span>How do I report a malicious extension?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>On the Visual Studio Marketplace, open the extension&#8217;s page and use the <strong>Report a concern<\/strong> link. For Cursor or Open VSX, contact Cursor support or the registry, and tell the genuine developer.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Are VS Code and Cursor extensions safe? A 10-step checklist to check an extension is genuine before you install it, settings that block bad updates, and what to do if you installed a fake.<\/p>\n","protected":false},"author":4,"featured_media":69286,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","footnotes":""},"categories":[7],"tags":[],"class_list":["post-69287","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-security"],"_links":{"self":[{"href":"https:\/\/www.quickonlinetips.com\/archives\/wp-json\/wp\/v2\/posts\/69287","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.quickonlinetips.com\/archives\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.quickonlinetips.com\/archives\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.quickonlinetips.com\/archives\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.quickonlinetips.com\/archives\/wp-json\/wp\/v2\/comments?post=69287"}],"version-history":[{"count":1,"href":"https:\/\/www.quickonlinetips.com\/archives\/wp-json\/wp\/v2\/posts\/69287\/revisions"}],"predecessor-version":[{"id":69316,"href":"https:\/\/www.quickonlinetips.com\/archives\/wp-json\/wp\/v2\/posts\/69287\/revisions\/69316"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.quickonlinetips.com\/archives\/wp-json\/wp\/v2\/media\/69286"}],"wp:attachment":[{"href":"https:\/\/www.quickonlinetips.com\/archives\/wp-json\/wp\/v2\/media?parent=69287"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.quickonlinetips.com\/archives\/wp-json\/wp\/v2\/categories?post=69287"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.quickonlinetips.com\/archives\/wp-json\/wp\/v2\/tags?post=69287"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}