CVE-2025-4236
📋 TL;DR
A critical buffer overflow vulnerability exists in PCMan FTP Server 2.0.7's MDIR command handler, allowing remote attackers to execute arbitrary code or crash the service. This affects anyone running the vulnerable FTP server version. The exploit is publicly available and can be launched remotely without authentication.
💻 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, or ransomware deployment
Likely Case
Service crash causing denial of service and potential system instability
If Mitigated
Limited impact if proper network segmentation and exploit prevention controls are in place
🎯 Exploit Status
Exploit code is publicly available and requires minimal technical skill to execute
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: Yes
Instructions:
1. Check for updated version from vendor
2. If no patch available, consider alternative FTP server solutions
3. Apply workarounds immediately
🔧 Temporary Workarounds
Disable FTP Service
windowsCompletely disable PCMan FTP Server if not required
net stop "PCMan FTP Server"
sc config "PCMan FTP Server" start= disabled
Network Segmentation
windowsRestrict access to FTP service using firewall rules
netsh advfirewall firewall add rule name="Block PCMan FTP" dir=in action=block protocol=TCP localport=21
🧯 If You Can't Patch
- Replace with alternative secure FTP server software
- Implement strict network access controls and monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check if PCMan FTP Server version 2.0.7 is installed and runningCheck Version:
Check program files directory or registry: HKEY_LOCAL_MACHINE\SOFTWARE\PCMan FTP ServerVerify Fix Applied:
Verify service is stopped or replaced with alternative software📡 Detection & Monitoring
Log Indicators:
- Multiple failed MDIR commands
- Unusual buffer overflow errors in FTP logs
- Service crash events
Network Indicators:
- Excessive MDIR command attempts from single source
- Malformed FTP packets targeting port 21
SIEM Query:
source="ftp.log" AND (command="MDIR" OR "buffer overflow")