CVE-2025-5049
📋 TL;DR
CVE-2025-5049 is a critical buffer overflow vulnerability in FreeFloat FTP Server 1.0's APPEND command handler that 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 to potentially gain control of affected systems.
💻 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, and persistent backdoor installation
Likely Case
Service disruption through denial of service and potential remote code execution leading to system compromise
If Mitigated
Service disruption only if proper network segmentation and exploit prevention controls are in place
🎯 Exploit Status
Public exploit code is available, making exploitation straightforward for attackers with basic skills
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: N/A
Restart Required: No
Instructions:
No official patch available. Consider migrating to a supported, actively maintained FTP server solution.
🔧 Temporary Workarounds
Disable APPEND Command
windowsDisable the vulnerable APPEND command handler in FreeFloat FTP Server configuration
Edit FreeFloat FTP Server configuration file to remove or disable APPEND command support
Network Access Control
windowsRestrict network access to FreeFloat FTP Server using firewall rules
netsh advfirewall firewall add rule name="Block_FreeFloat_FTP" dir=in action=block protocol=TCP localport=21
netsh advfirewall firewall add rule name="Block_FreeFloat_FTP_Passive" dir=in action=block protocol=TCP localport=1024-65535
🧯 If You Can't Patch
- Immediately isolate affected systems from internet and restrict internal network access
- Replace FreeFloat FTP Server with a modern, supported alternative like FileZilla Server, vsftpd, or ProFTPD
🔍 How to Verify
Check if Vulnerable:
Check if FreeFloat FTP Server 1.0 is installed and running on port 21/TCP. Use netstat -an | findstr :21 on Windows to identify listening services.Check Version:
Check FreeFloat FTP Server interface or configuration files for version information. Typically shows "FreeFloat FTP Server 1.0" in service banner.Verify Fix Applied:
Verify FreeFloat FTP Server is no longer running or has been replaced with alternative software. Test that APPEND command is disabled or returns error.📡 Detection & Monitoring
Log Indicators:
- Multiple failed APPEND command attempts
- Unusually large APPEND command parameters
- Service crash logs from FreeFloat FTP Server
Network Indicators:
- Excessive traffic to FTP port 21 with malformed APPEND commands
- Buffer overflow patterns in FTP protocol traffic
SIEM Query:
source="*ftp*" AND (command="APPEND" OR "CVE-2025-5049") | stats count by src_ip, dest_ip