CVE-2023-33876
📋 TL;DR
A use-after-free vulnerability in Foxit Reader 12.1.2.15332 allows arbitrary code execution when processing malicious PDF files with crafted JavaScript. Attackers can exploit this by tricking users into opening malicious PDFs or visiting malicious websites with the browser plugin enabled. This affects all users running the vulnerable version of Foxit Reader.
💻 Affected Systems
- Foxit Reader
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining the same privileges as the user running Foxit Reader, potentially leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Malware installation leading to credential theft, data exfiltration, or system disruption.
If Mitigated
Limited impact with proper application sandboxing and user privilege restrictions, potentially only crashing the application.
🎯 Exploit Status
Exploitation requires user interaction but is straightforward once malicious PDF is opened. Public technical details available in Talos reports.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 12.1.3 or later
Vendor Advisory: https://www.foxit.com/support/security-bulletins.html
Restart Required: Yes
Instructions:
1. Download latest Foxit Reader from official website. 2. Run installer. 3. Restart system. 4. Verify version is 12.1.3 or higher.
🔧 Temporary Workarounds
Disable JavaScript in Foxit Reader
allPrevents exploitation by disabling JavaScript execution in PDF files
Open Foxit Reader > File > Preferences > Trust Manager > Uncheck 'Enable JavaScript'
Disable Browser Plugin
allPrevents web-based exploitation through browser
Browser settings > Extensions/Add-ons > Disable Foxit Reader plugin
🧯 If You Can't Patch
- Restrict PDF file handling to alternative PDF readers without this vulnerability
- Implement application whitelisting to prevent unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Check Foxit Reader version in Help > About. If version is 12.1.2.15332 or earlier, system is vulnerable.Check Version:
On Windows: wmic product where name="Foxit Reader" get versionVerify Fix Applied:
Verify version is 12.1.3 or later in Help > About.📡 Detection & Monitoring
Log Indicators:
- Multiple Foxit Reader crashes
- Unusual PDF file access patterns
- JavaScript execution errors in Foxit logs
Network Indicators:
- Downloads of PDF files from suspicious sources
- Outbound connections from Foxit Reader process
SIEM Query:
process_name:"FoxitReader.exe" AND (event_id:1000 OR event_id:1001) | stats count by host