CVE-2025-5634
📋 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 by sending specially crafted NOOP commands. This affects all systems running the vulnerable FTP server version. Attackers can exploit this without authentication to potentially gain control of affected systems.
💻 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, ransomware deployment, or creation of persistent backdoors.
Likely Case
Service crash causing denial of service, with potential for remote code execution by skilled attackers using the public exploit.
If Mitigated
Service disruption or crash without code execution if exploit attempts are blocked by network controls or security software.
🎯 Exploit Status
Public exploit code is available, making this easily weaponizable. The NOOP command is standard FTP functionality, making exploitation straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: No
Instructions:
No official patch is available. Consider upgrading to a different FTP server solution or implementing workarounds.
🔧 Temporary Workarounds
Block NOOP Commands at Network Level
linuxUse network filtering to block or inspect NOOP commands sent to the FTP server
# Example using iptables to block NOOP commands
# iptables -A INPUT -p tcp --dport 21 -m string --string "NOOP" --algo bm -j DROP
Disable FTP Service
windowsStop and disable the PCMan FTP Server service
sc stop "PCMan FTP Server"
sc config "PCMan FTP Server" start= disabled
🧯 If You Can't Patch
- Isolate the FTP server in a restricted network segment with no internet access
- Implement strict firewall rules to limit FTP access to only trusted IP addresses
🔍 How to Verify
Check if Vulnerable:
Check if PCMan FTP Server version 2.0.7 is installed and running. Look for the service in Windows Services or check installed programs.Check Version:
Check Windows Programs and Features or run: wmic product where "name like 'PCMan%'" get versionVerify Fix Applied:
Verify the service is stopped or uninstalled. Check firewall rules are blocking FTP port 21 or restricting access.📡 Detection & Monitoring
Log Indicators:
- Multiple NOOP commands in FTP logs
- Unusual FTP command sequences
- Service crash events in system logs
Network Indicators:
- Unusually large NOOP commands in FTP traffic
- Multiple connection attempts with NOOP commands
- Traffic patterns matching known exploit signatures
SIEM Query:
source="ftp_logs" AND command="NOOP" AND (size>100 OR count>5)