CVE-2025-5595 Overview
CVE-2025-5595 is a buffer overflow vulnerability in FreeFloat FTP Server 1.0. The flaw resides in the PROGRESS command handler, where improper bounds checking allows remote attackers to corrupt memory. Exploitation requires no authentication and can be triggered over the network by sending a crafted PROGRESS command to the FTP service.
The vulnerability is classified under [CWE-119], improper restriction of operations within the bounds of a memory buffer. A public exploit has been disclosed, increasing the likelihood of opportunistic attacks against exposed FreeFloat FTP services.
Critical Impact
Unauthenticated remote attackers can trigger a buffer overflow in the PROGRESS command handler, leading to service disruption and potential memory corruption on hosts running FreeFloat FTP Server 1.0.
Affected Products
- FreeFloat FTP Server 1.0
- CPE: cpe:2.3:a:freefloat:freefloat_ftp_server:1.0:*:*:*:*:*:*:*
- Component: PROGRESS command handler
Discovery Timeline
- 2025-06-04 - CVE-2025-5595 published to NVD
- 2025-06-24 - Last updated in NVD database
Technical Details for CVE-2025-5595
Vulnerability Analysis
The vulnerability exists in the PROGRESS command handler of FreeFloat FTP Server 1.0. The handler accepts attacker-controlled input without enforcing a proper length boundary on the supplied argument. Sending an oversized argument to the PROGRESS command causes the server to write beyond the allocated buffer.
This overflow can corrupt adjacent stack or heap structures depending on how the FTP server allocates its command parsing buffers. Attackers can crash the FTP service or attempt to manipulate control-flow data, depending on memory layout and protections compiled into the binary. The exploit code has been publicly disclosed through third-party exploit databases.
Root Cause
The root cause is missing input length validation in the PROGRESS command parser. FreeFloat FTP Server copies the supplied command argument into a fixed-size buffer without verifying that the input fits within the destination. This pattern, tracked as [CWE-119], leads to writes beyond buffer bounds whenever the supplied string exceeds the expected size.
Attack Vector
The attack vector is network-based and requires no authentication or user interaction. An attacker establishes a TCP connection to the FTP service, optionally authenticates if anonymous access is permitted, and sends a PROGRESS command with an oversized argument. The malformed command triggers the overflow inside the command handler, resulting in service disruption or memory corruption.
No verified proof-of-concept code is reproduced here. Refer to the Fitoxs Exploit Analysis and VulDB entry #311081 for technical details on the public exploit.
Detection Methods for CVE-2025-5595
Indicators of Compromise
- Unexpected crashes or restarts of the FreeFloat FTP Server process
- FTP server logs containing PROGRESS commands followed by abnormally long argument strings
- Inbound TCP traffic to port 21 from unfamiliar external sources targeting FreeFloat banners
- Memory access violations or Windows Error Reporting entries tied to the FreeFloat FTP binary
Detection Strategies
- Inspect FTP command logs for PROGRESS requests with argument lengths exceeding typical command sizes
- Deploy network IDS signatures that match oversized FTP command arguments on port 21
- Correlate FTP service termination events with preceding inbound connections to detect exploitation attempts
Monitoring Recommendations
- Enable verbose FTP command logging on hosts running FreeFloat FTP Server
- Forward host crash telemetry and FTP logs to a centralized SIEM for correlation
- Alert on repeated short-lived FTP sessions from the same source, which can indicate fuzzing or exploit attempts
How to Mitigate CVE-2025-5595
Immediate Actions Required
- Remove FreeFloat FTP Server 1.0 from production environments where a maintained alternative is available
- Block inbound access to FTP port 21 from untrusted networks at the perimeter firewall
- Restrict FTP access to known administrative IP ranges using host-based firewall rules
- Monitor exposed FTP services with network segmentation and rate limiting
Patch Information
No vendor patch is available. FreeFloat FTP Server 1.0 appears to be unmaintained, and no fixed version has been published through the references tracked in NVD or VulDB. Organizations should plan migration to a supported FTP or SFTP server such as vsftpd, proftpd, or an SFTP-capable solution that enforces modern memory safety practices.
Workarounds
- Disable the FreeFloat FTP Server service if it is not strictly required
- Place the FTP service behind a VPN to remove direct internet exposure
- Use an application-layer proxy or FTP gateway capable of filtering malformed PROGRESS commands
- Replace the affected software with a maintained FTP/SFTP implementation
# Example: block inbound FTP access from untrusted networks on Windows
netsh advfirewall firewall add rule name="Block Inbound FTP" dir=in action=block protocol=TCP localport=21
# Stop and disable the FreeFloat FTP Server service
sc stop "FreeFloat FTP Server"
sc config "FreeFloat FTP Server" start= disabled
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
