CVE-2020-6543
📋 TL;DR
This is a use-after-free vulnerability in Google Chrome's task scheduling component that allows remote attackers to potentially exploit heap corruption. Attackers can trigger this by tricking users into visiting a malicious HTML page, potentially leading to arbitrary code execution. All users running vulnerable Chrome 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...
Learn more about Chrome →Fedora by Fedoraproject
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with the privileges of the Chrome process, potentially leading to full system compromise if combined with privilege escalation vulnerabilities.
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 user interaction (visiting malicious page) but no authentication. The bug report suggests exploitation is feasible.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 84.0.4147.125 and later
Vendor Advisory: https://chromereleases.googleblog.com/2020/08/stable-channel-update-for-desktop.html
Restart Required: Yes
Instructions:
1. Open Chrome. 2. Click the three-dot menu. 3. Go to Help > About Google Chrome. 4. Chrome will automatically check for and install updates. 5. Click Relaunch to restart Chrome with the updated version.
🔧 Temporary Workarounds
Disable JavaScript
allPrevents exploitation by disabling JavaScript execution, which is required for the crafted HTML page to trigger the vulnerability.
Use Chrome's Site Isolation
allEnhances sandboxing to limit potential impact if exploitation occurs.
🧯 If You Can't Patch
- Restrict web browsing to trusted sites only using network policies or browser extensions.
- Implement application whitelisting to prevent unauthorized Chrome execution or use alternative browsers temporarily.
🔍 How to Verify
Check if Vulnerable:
Check Chrome version: If version is below 84.0.4147.125, the system is vulnerable.Check Version:
chrome://version/ (in Chrome address bar) or 'google-chrome --version' (Linux terminal)Verify Fix Applied:
Confirm Chrome version is 84.0.4147.125 or higher.📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports
- Unexpected process termination events
- Security event logs showing exploit attempts
Network Indicators:
- Traffic to known malicious domains hosting exploit code
- Unusual HTML/JavaScript patterns in web traffic
SIEM Query:
source="chrome" AND (event_type="crash" OR message="*use-after-free*" OR message="*heap corruption*")🔗 References
- https://chromereleases.googleblog.com/2020/08/stable-channel-update-for-desktop.html
- https://crbug.com/1104046
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EE7XWIZBME7JAY7N6CGPET4CLNHHEIVT/
- https://security.gentoo.org/glsa/202101-30
- https://www.debian.org/security/2021/dsa-4824
- https://chromereleases.googleblog.com/2020/08/stable-channel-update-for-desktop.html
- https://crbug.com/1104046
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EE7XWIZBME7JAY7N6CGPET4CLNHHEIVT/
- https://security.gentoo.org/glsa/202101-30
- https://www.debian.org/security/2021/dsa-4824
