CVE-2021-21142
📋 TL;DR
This is a use-after-free vulnerability in Google Chrome's Payments component on macOS that could allow a remote attacker to escape the browser sandbox. Attackers could exploit this by tricking users into visiting a malicious webpage, potentially gaining elevated privileges on the affected system. Users running Google Chrome on macOS prior to version 88.0.4324.146 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
Full system compromise via sandbox escape leading to arbitrary code execution with the privileges of the Chrome process, potentially allowing installation of malware, data theft, or system takeover.
Likely Case
Limited sandbox escape allowing attackers to execute code with elevated privileges, potentially leading to data exfiltration or further system exploitation.
If Mitigated
Attack fails due to updated Chrome version or sandbox hardening, resulting in no impact beyond failed exploit attempt.
🎯 Exploit Status
Exploitation requires crafting a malicious HTML page and convincing users to visit it. The use-after-free vulnerability in Payments component provides the sandbox escape vector.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 88.0.4324.146 and later
Vendor Advisory: https://chromereleases.googleblog.com/2021/02/stable-channel-update-for-desktop.html
Restart Required: Yes
Instructions:
1. Open Google Chrome. 2. Click the three-dot menu in top-right. 3. Go to Help > About Google Chrome. 4. Chrome will automatically check for updates and install version 88.0.4324.146 or later. 5. Click 'Relaunch' to restart Chrome with the update.
🔧 Temporary Workarounds
Disable JavaScript
allTemporarily disable JavaScript to prevent exploitation via malicious webpages
chrome://settings/content/javascript
Use alternative browser
allSwitch to an unaffected browser until Chrome is updated
🧯 If You Can't Patch
- Implement network filtering to block access to untrusted websites
- Enable enhanced browser sandboxing and security features
🔍 How to Verify
Check if Vulnerable:
Check Chrome version by navigating to chrome://version and verifying version is below 88.0.4324.146Check Version:
chrome://versionVerify Fix Applied:
Confirm Chrome version is 88.0.4324.146 or higher via chrome://version📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports with memory corruption signatures
- Unusual process creation from Chrome sandbox
Network Indicators:
- Requests to known exploit domains
- Unusual outbound connections from Chrome processes
SIEM Query:
process_name:chrome AND (event_id:1000 OR event_id:1001) AND version:<88.0.4324.146🔗 References
- https://chromereleases.googleblog.com/2021/02/stable-channel-update-for-desktop.html
- https://crbug.com/1169317
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7ACWYJ74Z3YN2XH4QMUEGNBC3VXX464L/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AUQSMNV7INLDDSD3RKI5S5EAULX2QC7P/
- https://security.gentoo.org/glsa/202104-08
- https://chromereleases.googleblog.com/2021/02/stable-channel-update-for-desktop.html
- https://crbug.com/1169317
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7ACWYJ74Z3YN2XH4QMUEGNBC3VXX464L/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AUQSMNV7INLDDSD3RKI5S5EAULX2QC7P/
- https://security.gentoo.org/glsa/202104-08
