CVE-2024-21385
📋 TL;DR
This vulnerability in Microsoft Edge allows attackers to gain elevated privileges on affected systems by exploiting a use-after-free memory corruption flaw. It affects users running vulnerable versions of Microsoft Edge on Windows systems. Successful exploitation could allow attackers to execute arbitrary code with higher privileges than intended.
💻 Affected Systems
- Microsoft Edge (Chromium-based)
📦 What is this software?
Edge Chromium by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with SYSTEM-level privileges, enabling installation of persistent malware, data theft, and lateral movement across the network.
Likely Case
Local privilege escalation allowing attackers to bypass security controls, install unwanted software, or access restricted system resources.
If Mitigated
Limited impact with proper patch management and security controls, potentially reduced to denial of service or application crash.
🎯 Exploit Status
Requires local access or ability to execute code in browser context. Likely requires chaining with other vulnerabilities for remote exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Microsoft Edge version 121.0.2277.128 or later
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21385
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 higher.
🔧 Temporary Workarounds
Disable Edge browser
windowsTemporarily disable Microsoft Edge to prevent exploitation while awaiting patch deployment
Set-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\Edge" -Name "BrowserEnabled" -Value 0 -Type DWord
Restrict browser execution
windowsUse application control policies to restrict Edge execution for non-essential users
🧯 If You Can't Patch
- Implement strict application control policies to limit Edge usage to essential personnel only
- Deploy enhanced monitoring for privilege escalation attempts and unusual Edge process behavior
🔍 How to Verify
Check if Vulnerable:
Check Edge version: edge://settings/help or run 'msedge --version' in command promptCheck Version:
msedge --versionVerify Fix Applied:
Confirm Edge version is 121.0.2277.128 or higher using edge://settings/help📡 Detection & Monitoring
Log Indicators:
- Unusual Edge process spawning with elevated privileges
- Edge crash reports with memory corruption signatures
- Security event logs showing privilege escalation attempts
Network Indicators:
- Unusual outbound connections from Edge processes with elevated privileges
- Traffic to known exploit hosting domains
SIEM Query:
EventID=4688 AND ProcessName="msedge.exe" AND NewProcessName contains "cmd.exe" OR NewProcessName contains "powershell.exe"