CVE-2025-5112: FreeFloat FTP Buffer Overflow Vulnerability

CVE-2025-5112 Overview

A critical buffer overflow vulnerability has been discovered in FreeFloat FTP Server 1.0 affecting the MGET Command Handler component. This flaw allows remote attackers to exploit improper memory handling when processing MGET commands, potentially leading to arbitrary code execution or system compromise. The vulnerability can be triggered remotely without authentication, making it particularly dangerous for exposed FTP servers.

Critical Impact

Remote attackers can exploit this buffer overflow vulnerability in FreeFloat FTP Server to execute arbitrary code or cause denial of service conditions through the MGET command handler without requiring authentication.

Affected Products

• FreeFloat FTP Server 1.0
• FreeFloat FTP Server installations with exposed MGET command functionality
• Systems running vulnerable FreeFloat FTP Server on network-accessible interfaces

Discovery Timeline

• 2025-05-23 - CVE-2025-5112 published to NVD
• 2025-06-24 - Last updated in NVD database

Technical Details for CVE-2025-5112

Vulnerability Analysis

This vulnerability exists within the MGET Command Handler component of FreeFloat FTP Server 1.0. The MGET command is typically used to retrieve multiple files from an FTP server in a single operation. When processing specially crafted MGET requests, the server fails to properly validate the length of user-supplied input before copying it into a fixed-size buffer in memory.

The vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-120 (Buffer Copy without Checking Size of Input), indicating that the core issue stems from inadequate bounds checking during memory operations. An attacker can supply an overly long argument to the MGET command, causing the server to write data beyond the allocated buffer boundaries.

Since this vulnerability is exploitable over the network without requiring prior authentication or user interaction, it presents a significant attack surface for any FreeFloat FTP Server instance accessible from untrusted networks. The exploit has been publicly disclosed, increasing the risk of widespread exploitation.

Root Cause

The root cause of CVE-2025-5112 is a classic buffer overflow condition resulting from the use of unsafe memory copy operations in the MGET command processing logic. The FreeFloat FTP Server fails to implement proper input length validation before copying user-controlled data into stack or heap buffers. This oversight allows attackers to overwrite adjacent memory locations, potentially including return addresses, function pointers, or other critical data structures that can be leveraged for code execution.

Attack Vector

The attack vector for this vulnerability is network-based, requiring an attacker to establish a connection to the vulnerable FTP server. The exploitation process involves:

1. Establishing an FTP connection to the target server
2. Sending a crafted MGET command with an oversized payload designed to overflow the internal buffer
3. Overwriting critical memory structures to hijack program execution flow
4. Achieving arbitrary code execution in the context of the FTP server process

The vulnerability can be exploited remotely without requiring authentication credentials. For detailed technical information about the exploit methodology, refer to the Fitoxs Exploit Report and VulDB Entry #310089.

Detection Methods for CVE-2025-5112

Indicators of Compromise

• Unusual FTP connection patterns with abnormally long MGET command arguments
• FTP server crashes or unexpected process terminations
• Memory access violations or segmentation faults in FTP server logs
• Anomalous outbound connections from the FTP server process following MGET requests

Detection Strategies

• Monitor FTP traffic for MGET commands exceeding normal parameter lengths (typically thousands of characters)
• Implement network intrusion detection rules to flag oversized FTP command arguments
• Deploy endpoint detection to identify buffer overflow exploitation attempts targeting FTP services
• Configure application-level firewalls to inspect and limit FTP command payload sizes

Monitoring Recommendations

• Enable verbose logging on FreeFloat FTP Server to capture all command activity
• Set up alerts for FTP service crashes or restarts that may indicate exploitation attempts
• Monitor system resource usage for anomalies that could suggest memory corruption
• Review network flow data for connections to the FTP port followed by unusual activity

How to Mitigate CVE-2025-5112

Immediate Actions Required

• Restrict network access to FreeFloat FTP Server to trusted IP addresses only
• Consider disabling the MGET command functionality if not operationally required
• Implement network segmentation to isolate FTP servers from critical infrastructure
• Deploy a web application firewall or network IPS with rules to detect buffer overflow attempts

Patch Information

No vendor patch information is currently available for this vulnerability. FreeFloat FTP Server 1.0 users should monitor the vendor for security updates. Given the age and abandonment status of this software, organizations are strongly encouraged to migrate to actively maintained FTP server alternatives such as FileZilla Server, vsftpd, or ProFTPD.

Additional technical details and vulnerability tracking information can be found at VulDB CTI ID #310089.

Workarounds

• Migrate to a modern, actively maintained FTP server solution as a long-term remediation
• Implement strict firewall rules limiting FTP access to known trusted networks only
• Use VPN or SSH tunneling to access FTP services instead of direct network exposure
• Consider replacing FTP with more secure file transfer protocols such as SFTP or SCP

# Example firewall configuration to restrict FTP access
# Allow FTP only from trusted network (192.168.1.0/24)
iptables -A INPUT -p tcp --dport 21 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 21 -j DROP

# Block oversized FTP commands at the network level (if supported)
# Note: Specific implementation varies by firewall/IPS solution