CVE-2023-42092
📋 TL;DR
This is a use-after-free vulnerability in Foxit PDF Reader's Doc object handling that allows remote attackers to execute arbitrary code. Attackers can exploit it by tricking users into opening malicious PDF files or visiting malicious web pages. All users running vulnerable versions of Foxit PDF Reader are affected.
💻 Affected Systems
- Foxit PDF Reader
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control of the victim's machine, data theft, ransomware deployment, and lateral movement within the network.
Likely Case
Local privilege escalation leading to data exfiltration, malware installation, and persistence establishment on the compromised system.
If Mitigated
Limited impact with sandboxing or application hardening preventing code execution, potentially resulting only in application crash.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file). The vulnerability is well-documented and weaponization is likely given the prevalence of PDF readers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2023.3 and later
Vendor Advisory: https://www.foxit.com/support/security-bulletins.html
Restart Required: Yes
Instructions:
1. Open Foxit PDF Reader
2. Go to Help > Check for Updates
3. Follow prompts to update to version 2023.3 or later
4. Restart the application
🔧 Temporary Workarounds
Disable JavaScript in Foxit Reader
windowsPrevents exploitation vectors that rely on JavaScript execution
Open Foxit Reader > File > Preferences > JavaScript > Uncheck 'Enable JavaScript'
Use Protected View
windowsOpens PDFs in sandboxed mode to limit potential damage
Open Foxit Reader > File > Preferences > General > Check 'Enable Safe Reading Mode'
🧯 If You Can't Patch
- Disable Foxit PDF Reader as default PDF handler and use alternative PDF readers
- Implement application whitelisting to block Foxit Reader execution
🔍 How to Verify
Check if Vulnerable:
Check Foxit Reader version: Open Foxit Reader > Help > About Foxit Reader. If version is below 2023.3, you are vulnerable.Check Version:
Not applicable - check via GUI as described aboveVerify Fix Applied:
Verify version is 2023.3 or higher in Help > About Foxit Reader. Test opening known safe PDF files to ensure functionality.📡 Detection & Monitoring
Log Indicators:
- Application crashes of FoxitReader.exe
- Unusual process creation from FoxitReader.exe
- Memory access violations in application logs
Network Indicators:
- Downloads of PDF files from untrusted sources
- Outbound connections initiated by FoxitReader.exe
SIEM Query:
Process:FoxitReader.exe AND (EventID:1000 OR ParentImage:FoxitReader.exe)