CVE-2025-5550 in FTP Server
Summary
by MITRE • 06/04/2025
A vulnerability was found in FreeFloat FTP Server 1.0 and classified as critical. Affected by this issue is some unknown functionality of the component PBSZ Command Handler. The manipulation leads to buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 06/24/2025
The vulnerability identified as CVE-2025-5550 represents a critical buffer overflow flaw within the FreeFloat FTP Server version 1.0, specifically impacting the PBSZ Command Handler component. This issue stems from inadequate input validation and memory management within the server's implementation of the PBSZ command, which is part of the FTP protocol's protection against buffer overflow attacks. The PBSZ command is designed to establish the protection buffer size for data connections in FTP transactions, making it a critical component in maintaining secure data transfer operations. The flaw allows attackers to manipulate the command handler through specially crafted PBSZ commands that exceed the allocated buffer space, potentially leading to arbitrary code execution or system compromise.
The technical exploitation of this vulnerability occurs through remote attack vectors, enabling malicious actors to send crafted PBSZ commands to the vulnerable FTP server instance. The buffer overflow condition manifests when the server fails to properly validate the length of data provided in the PBSZ command, allowing an attacker to overwrite adjacent memory locations with malicious payloads. This memory corruption can result in stack smashing, heap corruption, or other memory-related exploits that may lead to complete system compromise. The vulnerability's classification as critical reflects the ease with which remote attackers can leverage this flaw without requiring authentication, as the PBSZ command handler operates within the standard FTP protocol communication channels.
From an operational impact perspective, this vulnerability poses significant risks to organizations relying on FreeFloat FTP Server 1.0 for file transfer operations. The remote exploit capability means that attackers can compromise systems from anywhere on the network without requiring physical access or prior authentication. Successful exploitation could result in unauthorized access to sensitive data, complete system takeover, or the deployment of backdoors for persistent access. The disclosure of exploit code further amplifies the threat landscape, as it removes the requirement for advanced technical skills to carry out attacks against vulnerable systems. Organizations using this server version face potential data breaches, service disruptions, and compliance violations that could result in substantial financial and reputational damage.
Security mitigations for CVE-2025-5550 should prioritize immediate patching of the FreeFloat FTP Server to a version that addresses the buffer overflow in the PBSZ Command Handler. System administrators should implement network segmentation to limit access to FTP services and consider disabling unnecessary FTP features. The implementation of intrusion detection systems can help identify exploitation attempts through monitoring of anomalous PBSZ command patterns. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all instances of the affected software and ensure proper firewall rules are in place to restrict FTP traffic to authorized networks only. This vulnerability aligns with CWE-121, which describes buffer overflow conditions, and maps to ATT&CK technique T1190 for exploitation through remote services, highlighting the need for layered defensive strategies including network monitoring, access controls, and regular security updates to protect against such critical vulnerabilities in file transfer protocols.