CVE-2019-25321
📋 TL;DR
CVE-2019-25321 is a critical stack overflow vulnerability in FTP Navigator 8.03 that allows attackers to execute arbitrary code by exploiting Structured Exception Handler (SEH) overwrite. Attackers can trigger remote code execution by pasting a malicious payload into the Custom Command textbox. This affects all users running the vulnerable version of FTP Navigator.
💻 Affected Systems
- FTP Navigator
📦 What is this software?
Ftp Navigator by Internet Soft
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining complete control over the affected system, enabling data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Remote code execution leading to malware installation, data exfiltration, or system disruption, as demonstrated by the calculator proof-of-concept.
If Mitigated
Limited impact if proper network segmentation, application whitelisting, and least privilege principles are implemented.
🎯 Exploit Status
Exploit requires user to paste malicious payload into the application interface. Multiple public exploit proofs exist with working code execution demonstrations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: http://www.internet-soft.com/
Restart Required: No
Instructions:
1. Check vendor website for updated version. 2. Uninstall vulnerable version. 3. Install patched version if available. 4. Consider alternative FTP clients if no patch exists.
🔧 Temporary Workarounds
Disable Custom Command Feature
windowsRemove or restrict access to the Custom Command textbox functionality
Application Control Policy
windowsImplement application whitelisting to prevent execution of FTP Navigator
🧯 If You Can't Patch
- Replace FTP Navigator with alternative FTP client software
- Implement network segmentation to isolate systems running vulnerable software
🔍 How to Verify
Check if Vulnerable:
Check Help > About in FTP Navigator to verify version is 8.03Check Version:
Check application properties or Help > About menuVerify Fix Applied:
Verify installed version is newer than 8.03 or application has been removed📡 Detection & Monitoring
Log Indicators:
- Unusual process creation from FTP Navigator
- Calculator.exe or other unexpected processes launched
Network Indicators:
- Unusual outbound connections from FTP Navigator process
SIEM Query:
Process Creation where Parent Process contains 'ftpnav' OR Process Name contains 'calc'