CVE-2020-35629
📋 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 to execute arbitrary code on affected systems. Any application using CGAL for polygon parsing is potentially vulnerable.
💻 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 application context and memory protections.
If Mitigated
Application crash without code execution if modern exploit mitigations (ASLR, DEP) are effective, though information disclosure may still occur.
🎯 Exploit Status
Exploitation requires specially crafted polygon files and knowledge of the vulnerable parsing functionality. 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 any applications using CGAL. 3. Restart affected services. 4. For Linux distributions, use package manager: 'sudo apt update && sudo apt upgrade libcgal-dev' (Debian/Ubuntu) or 'sudo yum update CGAL' (RHEL/CentOS).
🔧 Temporary Workarounds
Disable Nef polygon parsing
allModify applications to avoid using CGAL's Nef polygon parsing functionality if not required.
Input validation
allImplement strict validation of polygon files before passing to CGAL parsing functions.
🧯 If You Can't Patch
- Network segmentation to isolate systems using CGAL
- Implement strict file upload controls and scanning for polygon files
🔍 How to Verify
Check if Vulnerable:
Check CGAL version: 'pkg-config --modversion cgal' or check installed packages for CGAL version 5.1.1 or earlier.Check Version:
pkg-config --modversion cgal || dpkg -l | grep libcgal || rpm -qa | grep -i cgalVerify Fix Applied:
Verify CGAL version is 5.1.2 or later using version check command and test polygon parsing functionality.📡 Detection & Monitoring
Log Indicators:
- Application crashes when processing polygon files
- Memory access violation errors in application logs
- Unexpected process termination of CGAL-based applications
Network Indicators:
- Unusual file uploads to applications using CGAL
- Network traffic patterns suggesting file transfer to vulnerable services
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
