CVE-2022-33034
📋 TL;DR
CVE-2022-33034 is a stack overflow vulnerability in LibreDWG's decode_r2007.c file that allows attackers to execute arbitrary code or cause denial of service by providing specially crafted DWG files. This affects users and applications that process DWG files with LibreDWG library versions 0.12.4.4608 and earlier. The vulnerability is triggered through the copy_bytes function when parsing malicious DWG files.
💻 Affected Systems
- LibreDWG
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with the privileges of the LibreDWG process, potentially leading to complete system compromise if the process runs with elevated privileges.
Likely Case
Application crash and denial of service when processing malicious DWG files, potentially disrupting CAD workflows or automated processing systems.
If Mitigated
Limited impact with proper sandboxing and privilege separation, potentially only causing application crashes without system compromise.
🎯 Exploit Status
Exploitation requires the victim to process a malicious DWG file. The vulnerability is in the core parsing logic, making reliable exploitation feasible. Proof-of-concept details are available in the GitHub issue.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v0.12.5 and later
Vendor Advisory: https://github.com/LibreDWG/libredwg/issues/494
Restart Required: Yes
Instructions:
1. Update LibreDWG to version 0.12.5 or later. 2. For Linux systems: Use package manager (apt/yum/dnf) to update libredwg packages. 3. For source installations: Download latest release from GitHub and rebuild. 4. Restart all applications and services using LibreDWG.
🔧 Temporary Workarounds
Input Validation and Sandboxing
allImplement strict input validation for DWG files and run LibreDWG processes in sandboxed environments with limited privileges.
Disable R2007 DWG Support
allIf possible, disable processing of R2007 DWG files which trigger the vulnerable code path.
🧯 If You Can't Patch
- Implement network segmentation to isolate systems using LibreDWG from untrusted networks
- Deploy application allowlisting to prevent execution of unauthorized binaries and restrict file processing capabilities
🔍 How to Verify
Check if Vulnerable:
Check LibreDWG version: 'dwgread --version' or 'strings /path/to/libredwg.so | grep -i version'. If version is 0.12.4.4608 or earlier, system is vulnerable.Check Version:
dwgread --version 2>/dev/null || strings $(ldconfig -p | grep libredwg | head -1 | awk '{print $4}') 2>/dev/null | grep -i versionVerify Fix Applied:
After update, verify version is 0.12.5 or later using 'dwgread --version'. Test with known safe DWG files to ensure functionality.📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults or stack overflow errors when processing DWG files
- Unusual memory consumption patterns in LibreDWG processes
Network Indicators:
- Unexpected DWG file uploads to web applications
- Network transfers of DWG files to internal systems
SIEM Query:
source="application_logs" AND (process="dwgread" OR process contains "libredwg") AND (message contains "segmentation fault" OR message contains "stack overflow" OR message contains "SIGSEGV")