CVE-2021-40160
📋 TL;DR
CVE-2021-40160 is an out-of-bounds read vulnerability in PDFTron PDF parsing libraries prior to version 9.0.7. Attackers can exploit this by crafting malicious PDF files to read beyond allocated memory boundaries, potentially leading to arbitrary code execution. This affects any application or service using vulnerable PDFTron libraries for PDF processing.
💻 Affected Systems
- PDFTron SDK
- Any software using PDFTron libraries for PDF processing
📦 What is this software?
Advance Steel by Autodesk
Autocad by Autodesk
Autocad by Autodesk
Autocad Lt by Autodesk
Autocad Lt by Autodesk
Autocad Mep by Autodesk
Civil 3d by Autodesk
Design Review by Autodesk
Design Review by Autodesk
Design Review by Autodesk
Design Review by Autodesk
Design Review by Autodesk
Navisworks by Autodesk
Navisworks by Autodesk
Navisworks by Autodesk
Navisworks by Autodesk
Revit by Autodesk
Revit by Autodesk
Revit by Autodesk
⚠️ Risk & Real-World Impact
Worst Case
Full remote code execution with the privileges of the PDF processing service, potentially leading to complete system compromise, data exfiltration, or lateral movement.
Likely Case
Application crash (denial of service) or limited information disclosure through memory reads, with code execution being possible but requiring specific memory layout conditions.
If Mitigated
Application crash contained within sandboxed environments, with no privilege escalation or data access beyond the PDF processing context.
🎯 Exploit Status
Exploitation requires crafting a malicious PDF file and getting it processed by a vulnerable system. The out-of-bounds read could potentially be leveraged for code execution with additional exploitation techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 9.0.7 and later
Vendor Advisory: https://www.autodesk.com/trust/security-advisories/adsk-sa-2021-0010
Restart Required: Yes
Instructions:
1. Identify all applications using PDFTron libraries. 2. Update PDFTron SDK to version 9.0.7 or later. 3. Rebuild and redeploy affected applications. 4. Restart services using the updated libraries.
🔧 Temporary Workarounds
Disable PDF processing
allTemporarily disable PDF file upload/processing functionality in affected applications
Sandbox PDF processing
allRun PDF processing in isolated containers or sandboxes with minimal privileges
🧯 If You Can't Patch
- Implement strict file upload validation to reject suspicious PDF files
- Deploy application-level firewalls or WAFs with PDF file inspection capabilities
🔍 How to Verify
Check if Vulnerable:
Check application dependencies for PDFTron libraries version <9.0.7Check Version:
Check package manifest files or use dependency scanning tools specific to your development environmentVerify Fix Applied:
Verify PDFTron version is 9.0.7 or higher in application dependencies📡 Detection & Monitoring
Log Indicators:
- Application crashes during PDF processing
- Memory access violation errors in logs
- Unusual PDF file processing patterns
Network Indicators:
- Unusual PDF file uploads to affected services
- PDF files with abnormal structure or size
SIEM Query:
source="application_logs" AND ("PDFTron" OR "PDF processing") AND ("crash" OR "access violation" OR "segmentation fault")