CVE-2021-30602
📋 TL;DR
This is a use-after-free vulnerability in Chrome's WebRTC component that allows heap corruption. Attackers can exploit it by tricking users into visiting malicious websites, potentially leading to arbitrary code execution. All Chrome users prior to version 92.0.4515.159 are affected.
💻 Affected Systems
- Google Chrome
- Chromium-based browsers
📦 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 with the privileges of the Chrome process, potentially leading to full system compromise if Chrome is running with elevated privileges.
Likely Case
Browser crash (denial of service) or limited code execution within Chrome's sandbox, potentially allowing data theft or further exploitation.
If Mitigated
No impact if Chrome is fully patched or if exploit attempts are blocked by security controls.
🎯 Exploit Status
Exploitation requires crafting malicious HTML/JavaScript and convincing users to visit it. The use-after-free in WebRTC makes reliable exploitation challenging but possible.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 92.0.4515.159
Vendor Advisory: https://chromereleases.googleblog.com/2021/08/stable-channel-update-for-desktop.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 apply updates. 4. Restart Chrome when prompted.
🔧 Temporary Workarounds
Disable WebRTC
allTemporarily disable WebRTC functionality to prevent exploitation
chrome://flags/#disable-webrtc
Set 'WebRTC' flag to 'Disabled'
Use Chrome Enterprise policies
allDeploy policies to block malicious sites and restrict WebRTC
Configure Site Isolation, Safe Browsing policies via GPO/management console
🧯 If You Can't Patch
- Deploy network filtering to block known malicious domains and restrict access to untrusted websites
- Implement application whitelisting to prevent unauthorized code execution from Chrome
🔍 How to Verify
Check if Vulnerable:
Check Chrome version: if below 92.0.4515.159, system is vulnerableCheck Version:
On Chrome: chrome://version/ or 'google-chrome --version' on command lineVerify Fix Applied:
Confirm Chrome version is 92.0.4515.159 or higher📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports with WebRTC-related stack traces
- Unexpected Chrome process termination
Network Indicators:
- Unusual WebRTC connections to external IPs
- Suspicious WebSocket/HTTP traffic to malicious domains
SIEM Query:
source="chrome_logs" AND (event="crash" OR event="exception") AND process="chrome" AND module="webrtc"🔗 References
- https://chromereleases.googleblog.com/2021/08/stable-channel-update-for-desktop.html
- https://crbug.com/1230767
- 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://www.talosintelligence.com/vulnerability_reports/TALOS-2021-1348
- https://chromereleases.googleblog.com/2021/08/stable-channel-update-for-desktop.html
- https://crbug.com/1230767
- 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://www.talosintelligence.com/vulnerability_reports/TALOS-2021-1348
