CVE-2020-22027
📋 TL;DR
A heap-based buffer overflow vulnerability in FFmpeg's neighbor filter allows attackers to execute arbitrary code or cause denial of service by processing specially crafted video files. This affects systems using FFmpeg 4.2 for video processing. The vulnerability is particularly dangerous in applications that process untrusted media files.
💻 Affected Systems
- FFmpeg
📦 What is this software?
Ffmpeg by Ffmpeg
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Application crash (denial of service) or memory corruption leading to unstable behavior.
If Mitigated
Limited impact with proper sandboxing and input validation, potentially just crashes.
🎯 Exploit Status
Proof-of-concept available in ticket attachments. Exploitation requires crafting a malicious video file that triggers the buffer overflow in the deflate16 function.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: FFmpeg 4.2.3 and later, or upgrade to FFmpeg 4.3+
Vendor Advisory: https://trac.ffmpeg.org/ticket/8242
Restart Required: Yes
Instructions:
1. Update FFmpeg to version 4.2.3 or later. 2. For Linux: Use package manager (apt-get upgrade ffmpeg, yum update ffmpeg). 3. For Windows/macOS: Download latest build from ffmpeg.org. 4. Restart any services using FFmpeg.
🔧 Temporary Workarounds
Disable neighbor filter
allRemove or disable the vf_neighbor filter if not required for functionality.
Modify FFmpeg configuration to exclude neighbor filter usage
Input validation and sandboxing
linuxImplement strict input validation for media files and run FFmpeg in sandboxed/containerized environment.
Use chroot, containers, or AppArmor/SELinux to restrict FFmpeg
🧯 If You Can't Patch
- Implement network segmentation to isolate FFmpeg processing systems
- Deploy application allowlisting to prevent execution of unauthorized FFmpeg processes
🔍 How to Verify
Check if Vulnerable:
Check FFmpeg version: ffmpeg -version | grep 'version' and verify if it's 4.2.2 or earlier.Check Version:
ffmpeg -version | grep 'version'Verify Fix Applied:
After update, confirm version is 4.2.3 or later: ffmpeg -version | grep 'version'📡 Detection & Monitoring
Log Indicators:
- FFmpeg segmentation faults
- Memory access violation errors
- Unexpected FFmpeg process termination
Network Indicators:
- Unusual outbound connections from media processing servers
- Large media uploads followed by system anomalies
SIEM Query:
source="*ffmpeg*" AND ("segmentation fault" OR "SIGSEGV" OR "buffer overflow")