CVE-2025-5547
📋 TL;DR
A critical buffer overflow vulnerability in FreeFloat FTP Server 1.0's CDUP command handler allows 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 with limited lateral movement if properly segmented
🎯 Exploit Status
Public exploit code available, making this easily weaponizable by attackers
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: N/A
Restart Required: No
Instructions:
No official patch available. 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
Network segmentation
windowsBlock FTP port (21) at network perimeter and internally
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 or vsftpd
- Implement strict network segmentation to isolate FTP server from critical systems
🔍 How to Verify
Check if Vulnerable:
Check if FreeFloat FTP Server 1.0 is installed and running on port 21Check Version:
Check program files directory for FreeFloat FTP Server installationVerify Fix Applied:
Verify service is stopped/disabled and port 21 is not listening📡 Detection & Monitoring
Log Indicators:
- Multiple failed CDUP commands
- Unusual buffer overflow errors in FTP logs
- Service crash events
Network Indicators:
- Excessive CDUP commands with long parameters
- Traffic patterns matching known exploit
SIEM Query:
source="ftp.log" AND (command="CDUP" AND length>100) OR (event_id=1000 AND process_name="FreeFloatFTPServer.exe")