CVE-2021-30627
📋 TL;DR
This vulnerability is a type confusion flaw in Chrome's Blink layout engine that allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. Attackers could execute arbitrary code or cause denial of service. All users running vulnerable Chrome versions 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 leading to full system compromise, data theft, or ransomware deployment.
Likely Case
Browser crash (denial of service) or limited code execution within browser sandbox.
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. Type confusion vulnerabilities often lead to reliable exploits.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 93.0.4577.82
Vendor Advisory: https://chromereleases.googleblog.com/2021/09/stable-channel-update-for-desktop.html
Restart Required: Yes
Instructions:
1. Open Chrome. 2. Click three-dot menu → Help → About Google Chrome. 3. Chrome will automatically check for and install updates. 4. Click 'Relaunch' to restart Chrome with the update.
🔧 Temporary Workarounds
Disable JavaScript
allPrevents exploitation by disabling JavaScript execution, which breaks most web functionality.
Use Chrome sandboxing
allEnsure Chrome sandbox is enabled to limit potential damage from exploitation.
🧯 If You Can't Patch
- Use alternative browsers until Chrome can be updated
- Implement web filtering to block known malicious sites and suspicious HTML content
🔍 How to Verify
Check if Vulnerable:
Check Chrome version: Open Chrome → Click three-dot menu → Help → About Google Chrome. If version is below 93.0.4577.82, you are vulnerable.Check Version:
On Windows: "C:\Program Files\Google\Chrome\Application\chrome.exe" --version
On Linux: google-chrome --version
On macOS: /Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --versionVerify Fix Applied:
Verify Chrome version is 93.0.4577.82 or higher using the same About Google Chrome page.📡 Detection & Monitoring
Log Indicators:
- Chrome crash reports
- Unexpected browser termination events
- Security event logs showing exploit attempts
Network Indicators:
- Requests to known exploit hosting domains
- Unusual HTML/JavaScript patterns in web traffic
SIEM Query:
source="chrome_logs" AND (event_type="crash" OR event_type="security_violation") AND version<"93.0.4577.82"🔗 References
- https://chromereleases.googleblog.com/2021/09/stable-channel-update-for-desktop.html
- https://crbug.com/1245786
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4DDW7HAHTS3SDVXBQUY4SURELO5D4X7R/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PM7MOYYHJSWLIFZ4TPJTD7MSA3HSSLV2/
- https://chromereleases.googleblog.com/2021/09/stable-channel-update-for-desktop.html
- https://crbug.com/1245786
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4DDW7HAHTS3SDVXBQUY4SURELO5D4X7R/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PM7MOYYHJSWLIFZ4TPJTD7MSA3HSSLV2/
