CVE-2020-28620
📋 TL;DR
This vulnerability allows remote code execution through specially crafted files in CGAL library's Nef polygon-parsing functionality. Attackers can exploit out-of-bounds read and type confusion vulnerabilities to execute arbitrary code. Systems using CGAL for computational geometry operations are affected.
💻 Affected Systems
- CGAL (Computational Geometry Algorithms Library)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining complete control over the affected system, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Application crash leading to denial of service, with potential for limited code execution depending on exploit sophistication and system protections.
If Mitigated
Application crash without code execution if modern exploit mitigations (ASLR, DEP) are effective, though denial of service still occurs.
🎯 Exploit Status
Exploitation requires specially crafted malformed files and knowledge of the vulnerable parsing functionality.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: CGAL-5.1.2 and later
Vendor Advisory: https://www.cgal.org/
Restart Required: Yes
Instructions:
1. Update CGAL library to version 5.1.2 or later
2. Recompile any applications using CGAL
3. Restart affected services or applications
🔧 Temporary Workarounds
Input validation and sanitization
allImplement strict validation of polygon files before processing with CGAL library
Sandbox CGAL processing
linuxRun CGAL operations in isolated containers or sandboxes with limited privileges
docker run --read-only --cap-drop=ALL -v /safe-input:/input:ro your-app
🧯 If You Can't Patch
- Implement strict file upload restrictions and validation for polygon files
- Isolate CGAL processing to dedicated systems with network segmentation
🔍 How to Verify
Check if Vulnerable:
Check CGAL version with: pkg-config --modversion cgal or check library files for version 5.1.1 or earlierCheck Version:
pkg-config --modversion cgal || grep 'CGAL_VERSION' /usr/include/CGAL/version.h 2>/dev/null || echo 'Check application documentation for CGAL version'Verify Fix Applied:
Verify CGAL version is 5.1.2 or later using same version check command📡 Detection & Monitoring
Log Indicators:
- Application crashes when processing polygon files
- Memory access violation errors in application logs
- Unexpected process termination of CGAL-dependent applications
Network Indicators:
- Unusual file uploads to applications using CGAL
- Network traffic spikes followed by application crashes
SIEM Query:
source="application.logs" AND ("segmentation fault" OR "access violation" OR "out of bounds") AND process="*cgal*"🔗 References
- https://lists.debian.org/debian-lts-announce/2022/12/msg00011.html
- https://security.gentoo.org/glsa/202305-34
- https://talosintelligence.com/vulnerability_reports/TALOS-2020-1225
- https://lists.debian.org/debian-lts-announce/2022/12/msg00011.html
- https://security.gentoo.org/glsa/202305-34
- https://talosintelligence.com/vulnerability_reports/TALOS-2020-1225
