CVE-2021-30567
📋 TL;DR
This is a use-after-free vulnerability in Chrome DevTools that could allow heap corruption. Attackers who convince users to open DevTools could potentially exploit this to execute arbitrary code. Users of Google Chrome versions prior to 92.0.4515.107 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
Remote code execution leading to full system compromise, data theft, or ransomware deployment.
Likely Case
Browser crash or limited code execution within the browser sandbox.
If Mitigated
No impact if Chrome is updated or DevTools access is restricted.
🎯 Exploit Status
Exploitation requires specific user gestures and DevTools interaction, making reliable exploitation challenging but possible.
🛠️ 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 the 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 DevTools via Group Policy
windowsPrevents users from opening DevTools, eliminating the attack vector.
Set 'DeveloperToolsAvailability' policy to 2 (Disallowed)
Disable DevTools via Chrome Flags
allDisables DevTools access through Chrome's experimental flags.
Navigate to chrome://flags/#disable-devtools and set to 'Disabled'
🧯 If You Can't Patch
- Restrict user permissions to prevent opening DevTools via browser settings or enterprise policies.
- Implement network filtering to block malicious websites that may trigger the vulnerability.
🔍 How to Verify
Check if Vulnerable:
Check Chrome version in Settings → About Chrome. If version is below 92.0.4515.107, the system is vulnerable.Check Version:
google-chrome --version (Linux), 'chrome://version' in address bar (all platforms)Verify Fix Applied:
Confirm Chrome version is 92.0.4515.107 or higher in Settings → About Chrome.📡 Detection & Monitoring
Log Indicators:
- Chrome crash logs with DevTools-related errors
- Unexpected DevTools process launches
Network Indicators:
- Unusual outbound connections from Chrome after DevTools usage
SIEM Query:
source="chrome_logs" AND (event="crash" OR event="devtools_launch")🔗 References
- https://chromereleases.googleblog.com/2021/07/stable-channel-update-for-desktop_20.html
- https://crbug.com/1211326
- 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/1211326
- 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/
