CVE-2025-4162
📋 TL;DR
A critical buffer overflow vulnerability in PCMan FTP Server's ASCII command handler allows remote attackers to execute arbitrary code or crash the service. This affects all versions up to 2.0.7. Organizations running vulnerable FTP servers are at risk of complete system compromise.
💻 Affected Systems
- PCMan FTP Server
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to full system compromise, data theft, ransomware deployment, or persistent backdoor installation
Likely Case
Service crash causing denial of service, with potential for RCE if exploit is weaponized
If Mitigated
Denial of service only if exploit attempts are blocked by network controls
🎯 Exploit Status
Public exploit code available, making weaponization straightforward for attackers
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: Yes
Instructions:
1. Check for updated version from vendor (none available as of analysis)
2. If no patch, implement workarounds or migrate to alternative FTP server
🔧 Temporary Workarounds
Disable ASCII mode
windowsForce binary-only transfers to bypass vulnerable ASCII handler
Configure FTP server to disable ASCII mode (server-specific configuration)
Network segmentation
allIsolate FTP server behind firewall with strict access controls
Firewall rules to restrict FTP access to trusted IPs only
🧯 If You Can't Patch
- Replace PCMan FTP Server with alternative secure FTP solution
- Implement application-layer firewall or WAF with buffer overflow protection
🔍 How to Verify
Check if Vulnerable:
Check PCMan FTP Server version in GUI or via 'About' menu. Versions ≤2.0.7 are vulnerableCheck Version:
Check version in PCMan FTP Server interface (no CLI version command)Verify Fix Applied:
Verify version is >2.0.7 when patch becomes available, or test with exploit PoC in controlled environment📡 Detection & Monitoring
Log Indicators:
- Multiple failed ASCII command attempts
- Unusual ASCII mode requests
- Server crash/restart events
Network Indicators:
- Excessive ASCII command traffic to FTP port 21
- Buffer overflow patterns in FTP traffic
SIEM Query:
source="ftp.log" AND (ascii OR "buffer overflow" OR crash)