CVE-2024-21399
📋 TL;DR
This vulnerability in Microsoft Edge (Chromium-based) allows remote attackers to execute arbitrary code on affected systems. Attackers could exploit this by tricking users into visiting a specially crafted website. All users running vulnerable versions of Microsoft Edge are affected.
💻 Affected Systems
- Microsoft Edge (Chromium-based)
📦 What is this software?
Edge Chromium by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining complete control over the victim's computer, enabling data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Malware installation leading to credential theft, data exfiltration, or system disruption through drive-by download attacks.
If Mitigated
Limited impact with proper security controls, potentially resulting in browser crash or sandbox escape without full system compromise.
🎯 Exploit Status
Exploitation requires user interaction (visiting malicious website) but no authentication. Based on CWE-416 (Use After Free), exploitation likely requires specific memory manipulation techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 121.0.2277.128
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21399
Restart Required: Yes
Instructions:
1. Open Microsoft Edge. 2. Click Settings (three dots) → Help and feedback → About Microsoft Edge. 3. Browser will automatically check for and install updates. 4. Restart Edge when prompted. 5. Verify version is 121.0.2277.128 or later.
🔧 Temporary Workarounds
Disable JavaScript
windowsTemporarily disable JavaScript to prevent exploitation vectors, though this will break most website functionality.
edge://settings/content/javascript
Use Enhanced Security Mode
windowsEnable Microsoft Edge's Enhanced Security Mode for additional protection layers.
edge://settings/privacy
🧯 If You Can't Patch
- Restrict access to untrusted websites using web filtering or proxy controls
- Implement application whitelisting to prevent unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Open Microsoft Edge, go to edge://settings/help and check if version is below 121.0.2277.128Check Version:
Start Microsoft Edge and navigate to edge://settings/helpVerify Fix Applied:
Open Microsoft Edge, go to edge://settings/help and confirm version is 121.0.2277.128 or higher📡 Detection & Monitoring
Log Indicators:
- Edge crash reports with suspicious memory addresses
- Unexpected child processes spawned from Edge
- Unusual network connections from Edge to unknown IPs
Network Indicators:
- Traffic to known malicious domains hosting exploit code
- Unusual outbound connections following Edge usage
SIEM Query:
Process Creation where ParentImage contains "msedge.exe" and CommandLine contains suspicious patterns