CVE-2020-23873
📋 TL;DR
CVE-2020-23873 is a critical heap-buffer overflow vulnerability in pdf2xml v2.0's TextPage::dump function that allows attackers to execute arbitrary code or cause denial of service. This affects any system running pdf2xml v2.0 to parse PDF files, particularly document processing systems and applications that convert PDF to XML. Attackers can exploit this by providing specially crafted PDF files to vulnerable systems.
💻 Affected Systems
- pdf2xml
📦 What is this software?
Pdf2xml by Science Miner
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with full system compromise, allowing attackers to install malware, steal data, or pivot to other systems.
Likely Case
Denial of service through application crashes, potentially leading to data loss or service disruption in document processing workflows.
If Mitigated
Contained application crash with no privilege escalation if proper sandboxing and memory protections are implemented.
🎯 Exploit Status
Proof-of-concept code is publicly available, making exploitation straightforward for attackers with basic skills.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 2.1 or later
Vendor Advisory: https://github.com/kermitt2/pdf2xml/issues/11
Restart Required: Yes
Instructions:
1. Download latest version from https://github.com/kermitt2/pdf2xml 2. Uninstall current version 3. Install version 2.1 or newer 4. Restart any services using pdf2xml
🔧 Temporary Workarounds
Disable PDF processing
linuxTemporarily disable pdf2xml functionality until patching is complete
sudo systemctl stop pdf2xml-service
sudo chmod 000 /usr/bin/pdf2xml
Input validation
allImplement strict file type validation and size limits for PDF uploads
🧯 If You Can't Patch
- Isolate pdf2xml in a container or VM with minimal privileges
- Implement network segmentation to restrict access to systems running pdf2xml
🔍 How to Verify
Check if Vulnerable:
Check if pdf2xml version 2.0 is installed: 'pdf2xml --version' or check package managerCheck Version:
pdf2xml --version 2>&1 | grep -i versionVerify Fix Applied:
Verify version is 2.1 or newer: 'pdf2xml --version' should show 2.1+📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults
- Unusual memory allocation patterns
- Repeated failed PDF processing attempts
Network Indicators:
- Unusual PDF file uploads to web applications
- Traffic patterns indicating exploitation attempts
SIEM Query:
source="application.log" AND ("segmentation fault" OR "heap overflow" OR "pdf2xml crash")🔗 References
- https://cwe.mitre.org/data/definitions/122.html
- https://github.com/Aurorainfinity/Poc/tree/master/pdf2xml
- https://github.com/kermitt2/pdf2xml/issues/11
- https://cwe.mitre.org/data/definitions/122.html
- https://github.com/Aurorainfinity/Poc/tree/master/pdf2xml
- https://github.com/kermitt2/pdf2xml/issues/11
