CVE-2022-30524
📋 TL;DR
CVE-2022-30524 is an invalid memory access vulnerability in Xpdf's text extraction functionality that allows remote attackers to cause denial of service (segmentation fault) or potentially execute arbitrary code by sending a crafted PDF file. This affects systems running Xpdf's pdftotext binary or any software using Xpdf libraries for PDF processing. The vulnerability is triggered when processing PDFs with characters at large y coordinates.
💻 Affected Systems
- Xpdf
- pdftotext
- software using Xpdf libraries
📦 What is this software?
Xpdf by Xpdfreader
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise if memory corruption can be weaponized for arbitrary code execution.
Likely Case
Denial of service through application crash (segmentation fault) when processing malicious PDFs.
If Mitigated
Limited impact with proper sandboxing, input validation, and memory protection mechanisms in place.
🎯 Exploit Status
Exploitation requires sending a crafted PDF file to vulnerable systems. The vulnerability is in the core text extraction logic.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Xpdf 4.0.5 and later
Vendor Advisory: https://forum.xpdfreader.com/viewtopic.php?f=3&t=42261
Restart Required: No
Instructions:
1. Download Xpdf 4.0.5 or later from https://www.xpdfreader.com/download.html
2. Compile and install the updated version
3. Replace existing pdftotext binary with patched version
4. Recompile any software using Xpdf libraries with updated version
🔧 Temporary Workarounds
Disable PDF text extraction
linuxDisable or restrict access to pdftotext binary and Xpdf functionality
chmod 000 /usr/bin/pdftotext
mv /usr/bin/pdftotext /usr/bin/pdftotext.disabled
Sandbox PDF processing
linuxRun pdftotext in a container or sandbox with limited privileges
docker run --read-only --cap-drop=ALL -v /tmp:/tmp:ro pdftotext-container
🧯 If You Can't Patch
- Implement strict input validation to reject PDFs with suspicious coordinate values
- Deploy memory protection mechanisms like ASLR and DEP to reduce exploitability
🔍 How to Verify
Check if Vulnerable:
Check Xpdf version: pdftotext -v 2>&1 | grep versionCheck Version:
pdftotext -v 2>&1 | grep -o 'version [0-9.]*'Verify Fix Applied:
Verify version is 4.0.5 or later and test with known malicious PDF samples📡 Detection & Monitoring
Log Indicators:
- Segmentation fault errors in system logs
- pdftotext process crashes
- Abnormal PDF processing failures
Network Indicators:
- Unusual PDF file uploads to systems with Xpdf
- Multiple PDF processing attempts followed by service disruption
SIEM Query:
process_name="pdftotext" AND (event_type="crash" OR exit_code=139)