CVE-2021-29279
📋 TL;DR
This integer overflow vulnerability in GPAC's filter_props.c allows attackers to trigger a memcpy failure by providing a negative size value, potentially leading to memory corruption. It affects GPAC multimedia framework users who process untrusted media files. Successful exploitation could result in denial of service or arbitrary code execution.
💻 Affected Systems
- GPAC Multimedia Framework
📦 What is this software?
Gpac by Gpac
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise if the memory corruption can be weaponized into reliable exploitation.
Likely Case
Denial of service through application crash when processing malicious media files.
If Mitigated
Application crash with no further impact if memory protections (ASLR, DEP) prevent code execution.
🎯 Exploit Status
Exploitation requires crafting malicious media files that trigger the integer overflow. No public exploit code has been identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: GPAC versions after commit da69ad1f970a7e17c865eaec9af98cc84df10d5b
Vendor Advisory: https://github.com/gpac/gpac/commit/da69ad1f970a7e17c865eaec9af98cc84df10d5b
Restart Required: Yes
Instructions:
1. Update GPAC to latest version from official repository. 2. Rebuild from source if using custom builds. 3. Restart any services using GPAC libraries.
🔧 Temporary Workarounds
Input validation for media files
allImplement strict validation of media file inputs before processing with GPAC
Sandbox GPAC processing
linuxRun GPAC in containerized or sandboxed environment to limit impact of potential exploitation
docker run --security-opt=no-new-privileges -v /media:/media gpac-container
🧯 If You Can't Patch
- Implement network segmentation to isolate GPAC servers from critical systems
- Deploy application-level firewalls to filter and inspect media file uploads
🔍 How to Verify
Check if Vulnerable:
Check GPAC version: gpac -version. If version is 1.0.1 or earlier, system is vulnerable.Check Version:
gpac -version 2>/dev/null || gpac --version 2>/dev/null || echo 'GPAC not installed'Verify Fix Applied:
Verify GPAC version is newer than 1.0.1 and includes commit da69ad1f970a7e17c865eaec9af98cc84df10d5b in git history.📡 Detection & Monitoring
Log Indicators:
- GPAC process crashes
- Memory access violation errors in system logs
- Abnormal termination of media processing services
Network Indicators:
- Unusual media file upload patterns
- Large media files with unexpected properties
SIEM Query:
process:gpac AND (event_type:crash OR exit_code:139 OR exit_code:-1073741819)