CVE-2021-40752
📋 TL;DR
Adobe After Effects versions 18.4 and earlier contain a memory corruption vulnerability when processing malicious .m4a files. This could allow attackers to execute arbitrary code with the privileges of the current user. Users must open a specially crafted file to trigger the exploit.
💻 Affected Systems
- Adobe After Effects
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining the same privileges as the logged-in user, potentially leading to data theft, ransomware deployment, or lateral movement.
Likely Case
Local privilege escalation leading to data exfiltration, malware installation, or persistence mechanisms on the affected system.
If Mitigated
Limited impact with proper user awareness training and file restrictions preventing malicious file execution.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file) and memory corruption exploitation skills.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: After Effects 18.4.1 or later
Vendor Advisory: https://helpx.adobe.com/security/products/after_effects/apsb21-79.html
Restart Required: Yes
Instructions:
1. Open Adobe Creative Cloud application. 2. Navigate to Updates section. 3. Install After Effects update to version 18.4.1 or later. 4. Restart After Effects and system if prompted.
🔧 Temporary Workarounds
Block .m4a file extensions
windowsPrevent After Effects from opening .m4a files via file association changes
User awareness training
allTrain users to avoid opening unexpected .m4a files from untrusted sources
🧯 If You Can't Patch
- Restrict user permissions to limit damage from successful exploitation
- Implement application whitelisting to prevent unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Check After Effects version via Help > About After Effects menuCheck Version:
Not applicable - use GUI menu Help > About After EffectsVerify Fix Applied:
Verify version is 18.4.1 or higher in About dialog📡 Detection & Monitoring
Log Indicators:
- After Effects crash logs with .m4a file references
- Unexpected process execution from After Effects
Network Indicators:
- Outbound connections from After Effects process post-crash
SIEM Query:
Process:After Effects AND (Event:Crash OR FileExtension:.m4a)