CVE-2020-28618
📋 TL;DR
This vulnerability in CGAL library allows remote code execution through specially crafted polygon files. Attackers can exploit out-of-bounds read and type confusion vulnerabilities in Nef polygon parsing to potentially 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 code execution privileges equal to the CGAL process, potentially leading to data theft, system takeover, or lateral movement.
Likely Case
Application crash (denial of service) or limited code execution within the application context, potentially leading to data leakage.
If Mitigated
Application crash with no code execution if memory protections (ASLR, DEP) are effective, but information disclosure may still occur.
🎯 Exploit Status
Exploitation requires crafting malicious polygon files and convincing users/processes to parse them. No public exploit code has been identified.
🛠️ 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 to version 5.1.2 or later. 2. Recompile applications using CGAL. 3. Restart affected services.
🔧 Temporary Workarounds
Disable Nef polygon parsing
allModify applications to avoid using CGAL's Nef polygon parsing functionality
# Requires source code modification to remove Nef polygon usage
Input validation
allImplement strict validation of polygon files before passing to CGAL
# Implement file validation in application code
🧯 If You Can't Patch
- Network segmentation to isolate CGAL applications
- Implement strict file upload controls and sandbox CGAL processing
🔍 How to Verify
Check if Vulnerable:
Check CGAL version: dpkg -l | grep libcgal (Debian/Ubuntu) or rpm -qa | grep -i cgal (RHEL/CentOS)Check Version:
cgal_create_cmake_script --version 2>/dev/null || echo "Check package manager"Verify Fix Applied:
Verify CGAL version is 5.1.2 or later and applications have been recompiled📡 Detection & Monitoring
Log Indicators:
- Application crashes when processing polygon files
- Memory access violation errors in application logs
Network Indicators:
- Unexpected polygon file uploads to CGAL applications
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
