CVE-2019-20914
📋 TL;DR
This vulnerability in GNU LibreDWG is a NULL pointer dereference that can cause application crashes or potentially allow arbitrary code execution when processing malicious DWG files. It affects all systems running vulnerable versions of LibreDWG that process untrusted DWG files. The high CVSS score indicates critical severity.
💻 Affected Systems
- GNU LibreDWG
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise if the NULL pointer dereference can be weaponized for memory corruption attacks.
Likely Case
Application crash (denial of service) when processing specially crafted DWG files, potentially causing data loss or service disruption.
If Mitigated
Limited impact with proper input validation and sandboxing, likely resulting only in application crashes.
🎯 Exploit Status
Exploitation requires crafting a malicious DWG file. While the NULL pointer dereference could lead to crashes, weaponization for RCE would require additional memory corruption techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.9.4 and later
Vendor Advisory: https://github.com/LibreDWG/libredwg/commit/3b837bb72d6b9ab4d563faa211f90efc257e3c96
Restart Required: Yes
Instructions:
1. Update LibreDWG to version 0.9.4 or later. 2. Recompile any applications using LibreDWG. 3. Restart affected services.
🔧 Temporary Workarounds
Input validation and sanitization
allImplement strict validation of DWG files before processing with LibreDWG
Sandboxing
linuxRun LibreDWG in a sandboxed environment with limited privileges
firejail --net=none --private /path/to/libredwg
🧯 If You Can't Patch
- Implement network segmentation to isolate systems running vulnerable LibreDWG versions
- Deploy application allowlisting to prevent execution of unauthorized binaries
🔍 How to Verify
Check if Vulnerable:
Check LibreDWG version: libredwg --version. If version is 0.9.3 or earlier, system is vulnerable.Check Version:
libredwg --versionVerify Fix Applied:
After updating, verify version is 0.9.4 or later and test with known malicious DWG files if available.📡 Detection & Monitoring
Log Indicators:
- Application crashes of LibreDWG or dependent applications
- Segmentation fault errors in system logs
Network Indicators:
- Unusual file transfers of DWG files to vulnerable systems
SIEM Query:
source="*syslog*" AND "segmentation fault" AND "libredwg"