CVE-2025-5076 Overview
A critical buffer overflow vulnerability has been discovered in FreeFloat FTP Server version 1.0. The vulnerability exists in the SEND Command Handler component, where improper memory boundary validation allows attackers to manipulate input data and trigger a buffer overflow condition. This vulnerability can be exploited remotely over the network without requiring authentication, making it particularly concerning for organizations running this FTP server software.
Critical Impact
Remote attackers can exploit this buffer overflow vulnerability in the SEND Command Handler to potentially crash the FTP server or execute arbitrary code, compromising server integrity and availability.
Affected Products
- FreeFloat FTP Server 1.0
- freefloat freefloat_ftp_server
Discovery Timeline
- 2025-05-22 - CVE-2025-5076 published to NVD
- 2025-06-23 - Last updated in NVD database
Technical Details for CVE-2025-5076
Vulnerability Analysis
This vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw resides in the SEND Command Handler of FreeFloat FTP Server, which fails to properly validate the length of user-supplied input before copying it into a fixed-size buffer.
When a malicious user sends a specially crafted SEND command with an excessively long argument, the server does not adequately check the input boundaries. This allows data to overflow beyond the allocated buffer space, potentially overwriting adjacent memory regions including return addresses and other critical data structures.
The network-accessible nature of FTP services combined with the lack of authentication requirements for exploiting this vulnerability significantly increases the attack surface. The exploit for this vulnerability has been publicly disclosed, which elevates the risk of active exploitation in the wild.
Root Cause
The root cause of CVE-2025-5076 is improper bounds checking in the SEND command processing routine. The vulnerable code accepts user input without validating its length against the destination buffer capacity, leading to a classic stack-based or heap-based buffer overflow condition depending on the memory allocation strategy used by the application.
Attack Vector
The attack can be launched remotely over the network by connecting to the FTP server and sending a malformed SEND command. An attacker would craft a request containing an oversized payload designed to overflow the buffer and potentially hijack program execution flow. The exploit requires no authentication, allowing any network-connected attacker to attempt exploitation.
The vulnerability affects the confidentiality, integrity, and availability of the system, potentially allowing attackers to read sensitive memory contents, modify application behavior, or cause denial of service through application crashes.
Detection Methods for CVE-2025-5076
Indicators of Compromise
- Unusual crash logs or core dumps from the FreeFloat FTP Server process
- FTP server service repeatedly restarting or becoming unresponsive
- Network traffic containing abnormally long SEND command parameters to port 21
- Evidence of buffer overflow exploitation attempts in network intrusion detection logs
Detection Strategies
- Implement network-based intrusion detection rules to identify oversized SEND command payloads targeting FTP servers
- Monitor FTP server process for unexpected crashes or memory access violations
- Deploy application-level logging to capture command inputs exceeding normal parameter lengths
- Use memory protection mechanisms to detect buffer overflow exploitation attempts
Monitoring Recommendations
- Enable enhanced logging for FTP command processing to capture potential exploitation attempts
- Configure alerting for FTP server process crashes or unexpected terminations
- Monitor network traffic to and from FTP servers for anomalous patterns
- Review system event logs for signs of process injection or privilege escalation following FTP service compromise
How to Mitigate CVE-2025-5076
Immediate Actions Required
- Disable or restrict access to FreeFloat FTP Server 1.0 until a patch is available
- Implement network-level access controls to limit FTP server exposure to trusted networks only
- Consider migrating to an alternative FTP server solution with active security maintenance
- Deploy network intrusion prevention systems with rules targeting buffer overflow exploitation attempts
Patch Information
No vendor patch information is currently available for this vulnerability. FreeFloat FTP Server appears to be legacy software that may no longer receive security updates. Organizations are advised to evaluate alternative FTP server solutions with active security support. For additional technical details, refer to the VulDB advisory and the Fitoxs exploit report.
Workarounds
- Place the FTP server behind a firewall and restrict access to trusted IP addresses only
- Disable the SEND command functionality if not required for business operations
- Implement input filtering at the network perimeter to block oversized FTP commands
- Consider using a reverse proxy or application firewall to sanitize FTP traffic before it reaches the server
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
