CVE-2021-27267
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code by tricking users into opening malicious PDF files containing specially crafted U3D objects. It affects Foxit PhantomPDF users running vulnerable versions, requiring user interaction to trigger the exploit.
💻 Affected Systems
- Foxit PhantomPDF
📦 What is this software?
Foxit Reader by Foxitsoftware
Phantompdf by Foxitsoftware
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through arbitrary code execution with current user privileges, potentially leading to data theft, ransomware deployment, or lateral movement.
Likely Case
Malware installation or data exfiltration through spear-phishing campaigns targeting users who open malicious PDF attachments.
If Mitigated
Limited impact with proper email filtering, user training, and application sandboxing preventing successful exploitation.
🎯 Exploit Status
Exploitation requires user interaction but uses common attack vectors (malicious PDF files). The vulnerability was disclosed through ZDI with technical details available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 10.1.1 or later
Vendor Advisory: https://www.foxitsoftware.com/support/security-bulletins.php
Restart Required: Yes
Instructions:
1. Download latest version from Foxit website. 2. Run installer. 3. Restart system. 4. Verify version is 10.1.1 or higher.
🔧 Temporary Workarounds
Disable U3D content processing
windowsConfigure Foxit PhantomPDF to disable U3D object rendering
Edit registry: HKEY_CURRENT_USER\Software\Foxit Software\PhantomPDF\Preferences\Security\EnableU3D = 0
Use alternative PDF viewer
allTemporarily use a different PDF application until patched
🧯 If You Can't Patch
- Implement application whitelisting to block unauthorized PDF viewers
- Deploy network segmentation to limit lateral movement if compromised
🔍 How to Verify
Check if Vulnerable:
Check Foxit PhantomPDF version in Help > About. If version is 10.1.0.37527 or earlier, system is vulnerable.Check Version:
wmic product where name="Foxit PhantomPDF" get versionVerify Fix Applied:
Verify version is 10.1.1 or higher in Help > About dialog.📡 Detection & Monitoring
Log Indicators:
- Application crashes in Foxit PhantomPDF
- Unusual process creation from Foxit processes
- Failed U3D object loading attempts
Network Indicators:
- Outbound connections from Foxit processes to unknown IPs
- DNS requests for suspicious domains after PDF opening
SIEM Query:
process_name:"FoxitPhantomPDF.exe" AND (event_id:1000 OR parent_process:explorer.exe AND child_process:cmd.exe)