CVE-2021-24095
📋 TL;DR
This is a DirectX Elevation of Privilege vulnerability that allows an authenticated attacker to execute arbitrary code with SYSTEM privileges on a vulnerable Windows system. It affects Windows operating systems where DirectX is enabled. Attackers need local access to exploit this vulnerability.
💻 Affected Systems
- Microsoft Windows
📦 What is this software?
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with SYSTEM privileges, allowing installation of malware, data theft, and persistence mechanisms.
Likely Case
Local privilege escalation from a standard user account to SYSTEM privileges, enabling lateral movement and persistence.
If Mitigated
Limited impact if proper patch management and least privilege principles are implemented.
🎯 Exploit Status
Exploitation requires local authenticated access. Proof-of-concept code has been published.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: February 2021 security updates (KB4601319, KB4601345, KB4601384, etc.)
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-24095
Restart Required: Yes
Instructions:
1. Apply February 2021 Windows security updates from Windows Update. 2. For enterprise environments, deploy updates via WSUS or SCCM. 3. Restart affected systems after patch installation.
🔧 Temporary Workarounds
Disable DirectX
windowsDisable DirectX functionality to prevent exploitation (not recommended for most systems).
Not recommended as it breaks graphics functionality
🧯 If You Can't Patch
- Implement strict least privilege principles - limit standard user accounts
- Monitor for privilege escalation attempts and suspicious process creation
🔍 How to Verify
Check if Vulnerable:
Check Windows version and if February 2021 security updates are installed. Vulnerable if running affected versions without patches.Check Version:
wmic os get caption,version,buildnumberVerify Fix Applied:
Verify KB4601319, KB4601345, or KB4601384 is installed via 'wmic qfe list' or 'Get-Hotfix' in PowerShell.📡 Detection & Monitoring
Log Indicators:
- Event ID 4688 with SYSTEM privileges from non-system processes
- Suspicious process creation with high privileges
Network Indicators:
- Not network exploitable - local privilege escalation only
SIEM Query:
EventID=4688 AND NewProcessName contains 'cmd.exe' OR 'powershell.exe' AND SubjectUserName!=SYSTEM AND TokenElevationType=%%1938