CVE-2020-23928
📋 TL;DR
CVE-2020-23928 is a heap-based buffer over-read vulnerability in GPAC's abst_box_read function that allows reading beyond allocated memory boundaries. This affects users of GPAC multimedia framework before version 1.0.1 who process malicious media files, potentially leading to information disclosure or application crashes.
💻 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 combined with other vulnerabilities, though buffer over-reads typically only allow information disclosure.
Likely Case
Application crash (denial of service) or information disclosure from heap memory, potentially exposing sensitive data.
If Mitigated
Limited impact with proper memory protections (ASLR, DEP) and sandboxing, likely resulting only in application crashes.
🎯 Exploit Status
Proof-of-concept exists in GitHub issues. Exploitation requires crafting malicious media files that trigger the buffer over-read.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.0.1 and later
Vendor Advisory: https://github.com/gpac/gpac/commit/8e05648d6b4459facbc783025c5c42d301fef5c3
Restart Required: Yes
Instructions:
1. Update GPAC to version 1.0.1 or later. 2. Recompile if using source. 3. Restart any services using GPAC.
🔧 Temporary Workarounds
Input Validation
allImplement strict input validation for media files before processing with GPAC
Sandbox Execution
linuxRun GPAC in a sandboxed environment with limited permissions
firejail --net=none gpac
bubblewrap --unshare-all --new-session gpac
🧯 If You Can't Patch
- Implement network segmentation to isolate GPAC instances
- Deploy application allowlisting to prevent execution of unauthorized GPAC processes
🔍 How to Verify
Check if Vulnerable:
Check GPAC version: gpac -version. If version is below 1.0.1, system is vulnerable.Check Version:
gpac -versionVerify Fix Applied:
Verify GPAC version is 1.0.1 or higher: gpac -version | grep -q '1\.0\.[1-9]\|1\.[1-9]\|2\.'📡 Detection & Monitoring
Log Indicators:
- GPAC segmentation faults
- Abnormal memory access errors in system logs
- Unexpected GPAC process termination
Network Indicators:
- Unusual media file uploads to systems using GPAC
- Multiple failed processing attempts
SIEM Query:
process_name:gpac AND (event_type:crash OR memory_violation)🔗 References
- https://cwe.mitre.org/data/definitions/126.html
- https://github.com/gpac/gpac/commit/8e05648d6b4459facbc783025c5c42d301fef5c3
- https://github.com/gpac/gpac/issues/1568
- https://github.com/gpac/gpac/issues/1569
- https://cwe.mitre.org/data/definitions/126.html
- https://github.com/gpac/gpac/commit/8e05648d6b4459facbc783025c5c42d301fef5c3
- https://github.com/gpac/gpac/issues/1568
- https://github.com/gpac/gpac/issues/1569
