CVE-2021-21154
📋 TL;DR
This vulnerability is a heap buffer overflow in Chrome's Tab Strip component that allows an attacker who has already compromised the renderer process to potentially escape Chrome's sandbox. It affects Google Chrome versions prior to 88.0.4324.182. Users who haven't updated Chrome are vulnerable to this sandbox escape attack.
💻 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
Full system compromise via sandbox escape leading to arbitrary code execution with system privileges.
Likely Case
Sandbox escape allowing attacker to execute code outside Chrome's restricted environment, potentially leading to data theft or further system compromise.
If Mitigated
Attack limited to Chrome's sandboxed renderer process with no system-level impact.
🎯 Exploit Status
Requires chaining with another vulnerability to first compromise the renderer process.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 88.0.4324.182
Vendor Advisory: https://chromereleases.googleblog.com/2021/02/stable-channel-update-for-desktop_16.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. Restart Chrome when prompted.
🔧 Temporary Workarounds
Disable Chrome auto-updates
allPrevents automatic updates which could interfere with manual patching process
🧯 If You Can't Patch
- Disable Chrome usage entirely and use alternative browser
- Implement application whitelisting to block Chrome execution
🔍 How to Verify
Check if Vulnerable:
Check Chrome version in Help > About Google Chrome. If version is below 88.0.4324.182, system is vulnerable.Check Version:
google-chrome --versionVerify Fix Applied:
Verify Chrome version is 88.0.4324.182 or higher in Help > About Google Chrome.📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports with heap corruption signatures
- Unexpected Chrome renderer process termination
Network Indicators:
- Unusual outbound connections from Chrome processes
- Traffic to known exploit hosting domains
SIEM Query:
process_name:"chrome.exe" AND (event_id:1000 OR event_id:1001) AND description:"heap"🔗 References
- https://chromereleases.googleblog.com/2021/02/stable-channel-update-for-desktop_16.html
- https://crbug.com/1173269
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BI6ZIJQYP5DFMYVX4J5OGOU2NQLEZ3SB/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FE5SIKEVYTMDCC5OSXGOM2KRPYLHYMQX/
- https://security.gentoo.org/glsa/202104-08
- https://chromereleases.googleblog.com/2021/02/stable-channel-update-for-desktop_16.html
- https://crbug.com/1173269
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BI6ZIJQYP5DFMYVX4J5OGOU2NQLEZ3SB/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FE5SIKEVYTMDCC5OSXGOM2KRPYLHYMQX/
- https://security.gentoo.org/glsa/202104-08
