CVE-2025-5356
📋 TL;DR
A critical buffer overflow vulnerability exists in FreeFloat FTP Server 1.0's BYE command handler, allowing remote attackers to execute arbitrary code or crash the service. This affects all deployments of FreeFloat FTP Server 1.0 with the vulnerable component enabled. Attackers can exploit this without authentication over the network.
💻 Affected Systems
- FreeFloat 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 only if exploit attempts are blocked by network controls
🎯 Exploit Status
Public exploit code is available, making this easily weaponizable. The buffer overflow is straightforward to trigger.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: N/A
Restart Required: No
Instructions:
No official patch exists. Consider migrating to a maintained FTP server solution.
🔧 Temporary Workarounds
Disable FreeFloat FTP Server
windowsStop and disable the FreeFloat FTP Server service
sc stop FreeFloatFTPServer
sc config FreeFloatFTPServer start= disabled
Block FTP port at firewall
windowsPrevent external access to the FTP server
netsh advfirewall firewall add rule name="Block FTP" dir=in action=block protocol=TCP localport=21
🧯 If You Can't Patch
- Replace FreeFloat FTP Server with a maintained alternative like FileZilla Server, vsftpd, or ProFTPD
- Implement strict network segmentation to isolate the FTP server from critical systems
🔍 How to Verify
Check if Vulnerable:
Check if FreeFloat FTP Server 1.0 is installed and running on port 21/TCPCheck Version:
Check program files directory for FreeFloat FTP Server files and version informationVerify Fix Applied:
Verify the service is stopped/disabled or replaced with alternative software📡 Detection & Monitoring
Log Indicators:
- Multiple BYE commands with excessive length
- Service crash events in Windows Event Log
- Unusual process creation from ftpserver.exe
Network Indicators:
- Excessive BYE command traffic to FTP port
- Buffer overflow patterns in FTP protocol
SIEM Query:
source="windows" AND (event_id=7034 OR process_name="ftpserver.exe") AND (command_line LIKE "%BYE%" OR termination_type="crash")