CVE-2023-42096
📋 TL;DR
This is a use-after-free vulnerability in Foxit PDF Reader's PDF file parsing that allows remote attackers to execute arbitrary code when a user opens a malicious PDF file. Attackers can leverage this to run code with the same privileges as the current user process. All users of affected Foxit PDF Reader versions are vulnerable.
💻 Affected Systems
- Foxit PDF Reader
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise via remote code execution leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Malware installation, credential theft, or lateral movement within the network when users open malicious PDFs from phishing emails or compromised websites.
If Mitigated
Limited impact with proper application sandboxing, least privilege principles, and network segmentation preventing lateral movement.
🎯 Exploit Status
Exploitation requires user interaction but is technically straightforward once a malicious PDF is crafted. ZDI has confirmed the vulnerability and exploitation details.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2024.1 and later
Vendor Advisory: https://www.foxit.com/support/security-bulletins.html
Restart Required: Yes
Instructions:
1. Download latest version from Foxit website. 2. Run installer. 3. Restart system. 4. Verify version is 2024.1 or higher.
🔧 Temporary Workarounds
Disable JavaScript in Foxit Reader
allPrevents JavaScript-based exploitation vectors in PDF files
Open Foxit Reader > File > Preferences > JavaScript > Uncheck 'Enable JavaScript'
Use Protected View
windowsOpen PDFs in sandboxed protected view mode
File > Preferences > Trust Manager > Check 'Enable Safe Reading Mode'
🧯 If You Can't Patch
- Block PDF files at email gateways and web proxies
- Implement application allowlisting to prevent unauthorized PDF reader execution
🔍 How to Verify
Check if Vulnerable:
Check Foxit Reader version: Help > About Foxit Reader. If version is below 2024.1, system is vulnerable.Check Version:
On Windows: wmic product where name="Foxit Reader" get versionVerify Fix Applied:
Verify version is 2024.1 or higher in Help > About Foxit Reader.📡 Detection & Monitoring
Log Indicators:
- Process creation from Foxit Reader with unusual command lines
- Memory access violations in Foxit Reader process logs
- Unexpected network connections from Foxit Reader process
Network Indicators:
- Outbound connections from Foxit Reader to unknown IPs
- DNS requests for suspicious domains following PDF file access
SIEM Query:
process_name:"FoxitReader.exe" AND (event_id:1 OR event_id:4688) AND command_line:"*powershell*" OR command_line:"*cmd*"