CVE-2025-4255
📋 TL;DR
A critical buffer overflow vulnerability in PCMan FTP Server 2.0.7 allows remote attackers to execute arbitrary code or crash the service via the RMD command handler. This affects all systems running the vulnerable FTP server version. Attackers can exploit this without authentication over the network.
💻 Affected Systems
- PCMan FTP Server
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Service crash causing denial of service, potentially followed by remote code execution.
If Mitigated
Service disruption but no system compromise if exploit attempts are blocked.
🎯 Exploit Status
Public exploit code exists, making weaponization straightforward for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: Yes
Instructions:
1. Check for vendor updates at official PCMan FTP Server website
2. If no patch exists, migrate to alternative FTP server software
3. Apply workarounds immediately
🔧 Temporary Workarounds
Block RMD command at firewall
linuxPrevent exploitation by blocking RMD commands to the FTP server
iptables -A INPUT -p tcp --dport 21 -m string --string "RMD" --algo bm -j DROP
Disable FTP service
windowsTemporarily disable the FTP service until patching is possible
sc stop "PCMan FTP Server"
sc config "PCMan FTP Server" start= disabled
🧯 If You Can't Patch
- Isolate the FTP server in a dedicated network segment with strict firewall rules
- Implement application-level firewall or WAF to filter malicious RMD commands
🔍 How to Verify
Check if Vulnerable:
Check FTP server version in application interface or installation directoryCheck Version:
Check application properties or installation directory for version informationVerify Fix Applied:
Verify version is no longer 2.0.7 or test with exploit PoC in controlled environment📡 Detection & Monitoring
Log Indicators:
- Multiple failed RMD commands
- Unusually long RMD command parameters
- FTP service crash logs
Network Indicators:
- RMD commands with excessive payload length
- FTP traffic patterns matching exploit code
SIEM Query:
source="ftp.log" AND command="RMD" AND (length>100 OR contains(buffer))