CVE-2020-23872
📋 TL;DR
CVE-2020-23872 is a NULL pointer dereference vulnerability in pdf2xml v2.0 that allows attackers to cause a denial of service (DoS) by crashing the application. This affects systems running pdf2xml v2.0 when processing malicious PDF files. Users and applications that convert PDF files to XML using this software are vulnerable.
💻 Affected Systems
- pdf2xml
📦 What is this software?
Pdf2xml by Science Miner
⚠️ Risk & Real-World Impact
Worst Case
Complete application crash leading to denial of service, potentially disrupting PDF processing workflows and dependent systems.
Likely Case
Application crash when processing specially crafted PDF files, requiring manual restart of the pdf2xml process.
If Mitigated
Minimal impact if proper input validation and error handling are implemented, with the application gracefully handling malformed files.
🎯 Exploit Status
Proof-of-concept code is publicly available, making exploitation straightforward for attackers with access to malicious PDF files.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check upstream repository for fixes
Vendor Advisory: https://github.com/kermitt2/pdf2xml/issues/10
Restart Required: Yes
Instructions:
1. Check the upstream GitHub repository for patches. 2. Apply available fixes or update to a patched version. 3. Restart any services using pdf2xml.
🔧 Temporary Workarounds
Input validation and sanitization
allImplement strict input validation for PDF files before processing with pdf2xml
Process isolation
linuxRun pdf2xml in isolated containers or sandboxes to limit impact of crashes
docker run --rm -v $(pwd):/data pdf2xml
🧯 If You Can't Patch
- Implement network segmentation to restrict access to pdf2xml services
- Monitor for application crashes and implement automatic restart mechanisms
🔍 How to Verify
Check if Vulnerable:
Check if pdf2xml version 2.0 is installed and being used for PDF processingCheck Version:
pdf2xml --version or check installation directory for version informationVerify Fix Applied:
Test with known malicious PDF files from PoC repositories to ensure application doesn't crash📡 Detection & Monitoring
Log Indicators:
- Application crash logs
- Segmentation fault errors
- Unexpected process termination
Network Indicators:
- Unusual PDF file uploads to systems using pdf2xml
SIEM Query:
source="application.log" AND ("segmentation fault" OR "null pointer" OR "pdf2xml crash")