CVE-2021-31470
📋 TL;DR
This vulnerability in Foxit Reader allows remote attackers to execute arbitrary code by tricking users into opening malicious PDF files containing specially crafted U3D objects. The flaw exists due to improper validation of U3D objects before performing operations on them. Users of affected Foxit Reader versions are at risk.
💻 Affected Systems
- Foxit Reader
📦 What is this software?
3d by Foxitsoftware
3d by Foxitsoftware
3d by Foxitsoftware
3d by Foxitsoftware
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise via remote code execution with user privileges, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Malicious actors deliver targeted phishing emails with malicious PDF attachments, leading to malware installation or credential theft on individual workstations.
If Mitigated
Limited impact with proper endpoint protection, application whitelisting, and user training preventing successful exploitation.
🎯 Exploit Status
Exploit requires user to open malicious PDF. Proof-of-concept code is publicly available through ZDI advisory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Foxit Reader 10.1.2 or later
Vendor Advisory: https://www.foxitsoftware.com/support/security-bulletins.php
Restart Required: Yes
Instructions:
1. Download latest Foxit Reader from official website. 2. Run installer. 3. Restart system. 4. Verify version is 10.1.2 or higher.
🔧 Temporary Workarounds
Disable U3D support
allDisable U3D object rendering in Foxit Reader settings
Open Foxit Reader > File > Preferences > Trust Manager > Disable U3D support
Use alternative PDF reader
allTemporarily use a different PDF reader that is not vulnerable
🧯 If You Can't Patch
- Implement application whitelisting to block unauthorized executables
- Deploy endpoint detection and response (EDR) to monitor for suspicious PDF file execution
🔍 How to Verify
Check if Vulnerable:
Check Foxit Reader version: Open Foxit Reader > Help > About. If version is 10.1.1.37576 or earlier, system is vulnerable.Check Version:
On Windows: wmic product where name="Foxit Reader" get versionVerify Fix Applied:
Verify version is 10.1.2 or higher in About dialog. Test with known safe PDF containing U3D objects.📡 Detection & Monitoring
Log Indicators:
- Foxit Reader crash logs with U3D-related errors
- Windows Event Logs showing unexpected process creation from Foxit Reader
Network Indicators:
- Outbound connections from Foxit Reader process to unknown IPs
- DNS requests for suspicious domains after PDF opening
SIEM Query:
process_name:"FoxitReader.exe" AND (event_id:1000 OR event_id:1001) AND message:"U3D"