CVE-2021-30571
📋 TL;DR
This vulnerability in Google Chrome DevTools allows a malicious extension to escape the browser's security sandbox when a user visits a crafted HTML page. Attackers could potentially execute arbitrary code outside Chrome's sandbox protections. All Chrome users with vulnerable versions are affected.
💻 Affected Systems
- Google Chrome
📦 What is this software?
Chrome by Google
Google Chrome is the world's most popular web browser, used by over 3 billion users globally across Windows, macOS, Linux, Android, and iOS platforms. As a Chromium-based browser developed by Google, Chrome dominates the browser market with approximately 65% market share, making it a critical compon...
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⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to execute arbitrary code with user privileges, install malware, steal sensitive data, and maintain persistence on the system.
Likely Case
Attackers convincing users to install malicious extensions that then exploit this vulnerability to escape Chrome's sandbox and perform limited system-level actions.
If Mitigated
With proper controls, impact is limited to the Chrome sandbox environment only, preventing system-level compromise.
🎯 Exploit Status
Requires social engineering to install malicious extension plus visiting crafted page. CVSS 9.6 indicates high exploitability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 92.0.4515.107 and later
Vendor Advisory: https://chromereleases.googleblog.com/2021/07/stable-channel-update-for-desktop_20.html
Restart Required: Yes
Instructions:
1. Open Chrome. 2. Click three-dot menu → Help → About Google Chrome. 3. Chrome will automatically check for and install updates. 4. Click 'Relaunch' to restart Chrome with the patched version.
🔧 Temporary Workarounds
Disable Chrome Extensions
allTemporarily disable all extensions to prevent malicious extension exploitation
chrome://extensions/ → toggle off all extensions
Restrict Extension Installation
windowsConfigure Chrome to prevent users from installing extensions
Group Policy: ExtensionInstallBlocklist = *
Registry: HKCU\Software\Policies\Google\Chrome\ExtensionInstallBlocklist = 1,*
🧯 If You Can't Patch
- Implement application whitelisting to prevent execution of unauthorized Chrome extensions
- Use network segmentation to isolate Chrome instances and limit lateral movement if compromised
🔍 How to Verify
Check if Vulnerable:
Check Chrome version: if version is less than 92.0.4515.107, system is vulnerableCheck Version:
chrome://version/ or 'google-chrome --version' (Linux) or check About ChromeVerify Fix Applied:
Confirm Chrome version is 92.0.4515.107 or higher📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports with DevTools-related errors
- Unexpected Chrome extension installation events
- Process creation from Chrome outside expected sandbox
Network Indicators:
- Connections to suspicious domains after visiting HTML pages with DevTools references
- Unusual outbound traffic patterns from Chrome processes
SIEM Query:
Process Creation where Parent Process contains 'chrome.exe' and Command Line contains unusual system commands🔗 References
- https://chromereleases.googleblog.com/2021/07/stable-channel-update-for-desktop_20.html
- https://crbug.com/1101897
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5LVY4WIWTVVYKQMROJJS365TZBKEARCF/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IPJPUSAWIJMQFBQQQYXAICLI4EKFQOH6/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QW4R2K5HVJ4R6XDZYOJCCFPIN2XHNS3L/
- https://chromereleases.googleblog.com/2021/07/stable-channel-update-for-desktop_20.html
- https://crbug.com/1101897
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5LVY4WIWTVVYKQMROJJS365TZBKEARCF/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IPJPUSAWIJMQFBQQQYXAICLI4EKFQOH6/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QW4R2K5HVJ4R6XDZYOJCCFPIN2XHNS3L/
