CVE-2021-31451
📋 TL;DR
This vulnerability in Foxit Reader allows remote attackers to execute arbitrary code by tricking users into opening malicious PDF files or visiting malicious web pages. The flaw exists in how Annotation objects are handled, enabling attackers to run code with the same privileges as the current user. Users of affected Foxit Reader versions are at risk.
💻 Affected Systems
- Foxit Reader
📦 What is this software?
Foxit Reader by Foxitsoftware
Phantompdf by Foxitsoftware
Phantompdf by Foxitsoftware
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise via remote code execution, allowing attackers to install malware, steal data, or pivot to other systems.
Likely Case
Malware installation or data theft through targeted phishing campaigns using malicious PDF attachments.
If Mitigated
Limited impact if proper application sandboxing, least privilege principles, and network segmentation are implemented.
🎯 Exploit Status
Exploitation requires user interaction but is straightforward once malicious content is delivered. ZDI-CAN-13089 reference indicates professional research.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 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 to update
3. Restart computer after installation
🔧 Temporary Workarounds
Disable JavaScript in Foxit Reader
allPrevents execution of malicious scripts that could trigger the vulnerability
Open Foxit Reader > File > Preferences > JavaScript > Uncheck 'Enable JavaScript'
Use Protected View
allOpen PDFs in restricted mode to limit potential damage
Open Foxit Reader > File > Preferences > Trust Manager > Check 'Enable Safe Reading Mode'
🧯 If You Can't Patch
- Use alternative PDF readers that are not vulnerable
- Block PDF files from untrusted sources at email/web gateways
🔍 How to Verify
Check if Vulnerable:
Check Foxit Reader version in 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 later in Help > About.📡 Detection & Monitoring
Log Indicators:
- Foxit Reader crash logs with memory access violations
- Unexpected child processes spawned from Foxit Reader
Network Indicators:
- Downloads of PDF files from suspicious sources
- Outbound connections from Foxit Reader to unknown IPs
SIEM Query:
process_name:"FoxitReader.exe" AND (event_type:"process_creation" OR event_type:"crash")