CVE-2021-41360
📋 TL;DR
CVE-2021-41360 is a remote code execution vulnerability in Microsoft's HEVC Video Extensions that allows attackers to execute arbitrary code by tricking users into opening specially crafted media files. This affects Windows systems with the HEVC Video Extensions installed, potentially allowing attackers to gain control of affected systems.
💻 Affected Systems
- Microsoft HEVC Video Extensions
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining SYSTEM-level privileges, enabling data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Local privilege escalation leading to malware installation, credential theft, or lateral movement within the network.
If Mitigated
Limited impact due to application sandboxing or restricted user permissions, potentially only causing application crashes.
🎯 Exploit Status
Exploitation requires user interaction to open a malicious media file. No public exploit code was available at the time of disclosure.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: HEVC Video Extensions version with November 2021 security updates
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-41360
Restart Required: No
Instructions:
1. Open Microsoft Store. 2. Search for 'HEVC Video Extensions'. 3. Click 'Get Updates' or check for updates. 4. Install available updates. 5. Alternatively, install Windows Update KB5007186 (November 2021 cumulative update).
🔧 Temporary Workarounds
Disable HEVC Video Extensions
windowsTemporarily disable or uninstall the HEVC Video Extensions to prevent exploitation
Settings > Apps > Apps & features > HEVC Video Extensions > Uninstall
Restrict media file execution
windowsConfigure Group Policy to restrict execution of media files from untrusted sources
gpedit.msc > Computer Configuration > Administrative Templates > Windows Components > Attachment Manager
🧯 If You Can't Patch
- Implement application whitelisting to prevent execution of unauthorized media players
- Deploy email/web filtering to block suspicious media file attachments
🔍 How to Verify
Check if Vulnerable:
Check HEVC Video Extensions version in Microsoft Store or via PowerShell: Get-AppxPackage -Name Microsoft.HEVCVideoExtension*Check Version:
Get-AppxPackage -Name Microsoft.HEVCVideoExtension* | Select-Object VersionVerify Fix Applied:
Verify HEVC Video Extensions version is updated to November 2021 or later release📡 Detection & Monitoring
Log Indicators:
- Application crashes in HEVCVideoExtension.exe
- Windows Error Reporting events related to HEVC codec
- Unexpected process creation from media player applications
Network Indicators:
- Unusual outbound connections from media player processes
- Downloads of suspicious media files
SIEM Query:
EventID=1000 OR EventID=1001 AND SourceName='Application Error' AND ProcessName='HEVCVideoExtension.exe'