CVE-2025-4240
📋 TL;DR
A critical buffer overflow vulnerability exists in PCMan FTP Server 2.0.7's LCD Command Handler component, allowing remote attackers to execute arbitrary code or crash the service. This affects all systems running the vulnerable version of PCMan FTP Server. The exploit is publicly available and can be triggered without authentication.
💻 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 exploit is weaponized.
If Mitigated
Service disruption only if exploit attempts are blocked at network perimeter.
🎯 Exploit Status
Public exploit code exists and requires minimal technical skill to execute.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: Yes
Instructions:
1. Check vendor website for updates. 2. If no patch exists, upgrade to alternative FTP server software. 3. Uninstall PCMan FTP Server 2.0.7 if no fix is available.
🔧 Temporary Workarounds
Network Segmentation
allBlock FTP port 21 at network perimeter to prevent external exploitation.
firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="0.0.0.0/0" port protocol="tcp" port="21" reject'
netsh advfirewall firewall add rule name="Block FTP" dir=in action=block protocol=TCP localport=21
Service Disablement
windowsStop and disable PCMan FTP Server service.
sc stop "PCMan FTP Server"
sc config "PCMan FTP Server" start= disabled
🧯 If You Can't Patch
- Replace PCMan FTP Server with alternative FTP server software like FileZilla Server or vsftpd.
- Implement strict network access controls to limit FTP server exposure to trusted IPs only.
🔍 How to Verify
Check if Vulnerable:
Check installed version via Windows Programs and Features or by examining the executable properties.Check Version:
wmic product where name="PCMan FTP Server" get versionVerify Fix Applied:
Verify PCMan FTP Server 2.0.7 is uninstalled or replaced with different software.📡 Detection & Monitoring
Log Indicators:
- Multiple connection attempts to FTP port 21 followed by service crash
- Unusual process creation from FTP service executable
Network Indicators:
- Exploit traffic patterns matching public PoC
- Excessive malformed FTP commands to LCD handler
SIEM Query:
source="ftp.log" AND (command="LCD" OR command="CWD") AND size>256