CVE-2025-5637 in FTP Server
Summary
by MITRE • 06/05/2025
A vulnerability, which was classified as critical, was found in PCMan FTP Server 2.0.7. Affected is an unknown function of the component SYSTEM Command Handler. The manipulation leads to buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 06/25/2025
The vulnerability identified as CVE-2025-5637 represents a critical buffer overflow flaw within PCMan FTP Server version 2.0.7, specifically within the SYSTEM Command Handler component. This type of vulnerability falls under the Common Weakness Enumeration category CWE-121, which encompasses buffer overflow conditions that occur when more data is written to a buffer than it can hold, potentially leading to memory corruption and arbitrary code execution. The affected system command handler processes input data from remote clients, creating a direct pathway for malicious actors to exploit this weakness through network-based attacks.
The technical implementation of this vulnerability allows remote attackers to manipulate the SYSTEM Command Handler through specially crafted input sequences that exceed the allocated buffer space. When the server processes these malformed inputs, the excess data overflows into adjacent memory regions, potentially corrupting critical program structures including return addresses, function pointers, or other control data. This memory corruption can be leveraged to redirect program execution flow, enabling attackers to execute arbitrary code with the privileges of the affected FTP server process. The remote exploitation capability means that adversaries do not require physical access or local network presence to carry out this attack, making it particularly dangerous for publicly accessible FTP servers.
The operational impact of CVE-2025-5637 extends beyond simple denial of service scenarios, as the buffer overflow could potentially allow full system compromise. An attacker who successfully exploits this vulnerability could gain unauthorized access to the server's file system, execute commands with elevated privileges, or establish persistent backdoors. The implications are particularly severe for organizations that rely on FTP servers for data transfer operations, as these systems often contain sensitive information and may serve as entry points for broader network infiltration. The public disclosure of exploitation methods further amplifies the risk, as it removes the element of surprise and provides threat actors with readily available attack vectors.
Security mitigation strategies for this vulnerability should prioritize immediate patching of all affected PCMan FTP Server installations, as this represents the most effective remediation approach. Organizations should also implement network segmentation to limit exposure of FTP services to trusted networks only, deploy intrusion detection systems to monitor for suspicious command sequences, and consider disabling unnecessary FTP server features. Additionally, implementing proper input validation and bounds checking within the SYSTEM Command Handler would help prevent similar vulnerabilities from occurring in future versions. The ATT&CK framework categorizes this vulnerability under T1210 - Exploitation of Remote Services, emphasizing the need for proper service hardening and network monitoring to detect and prevent exploitation attempts.