CVE-2025-3373 in FTP Server
Summary
by MITRE • 04/07/2025
A vulnerability has been found in PCMan FTP Server 2.0.7 and classified as critical. Affected by this vulnerability is an unknown functionality of the component SITE CHMOD Command Handler. The manipulation leads to buffer overflow. The attack can be launched remotely. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 05/24/2026
The vulnerability in PCMan FTP Server 2.0.7 represents a critical security flaw that exploits a buffer overflow condition within the SITE CHMOD Command Handler component. This particular vulnerability falls under the category of remote code execution threats, as it can be triggered through network-based attacks without requiring local system access. The buffer overflow occurs when the server processes maliciously crafted input through the SITE CHMOD command, which is typically used to modify file permissions on ftp servers. The flaw enables attackers to overwrite adjacent memory locations, potentially leading to arbitrary code execution or system compromise. Given that the vulnerability affects the core command handler functionality, any client capable of sending ftp commands can potentially exploit this weakness.
The technical implementation of this vulnerability demonstrates a classic buffer overflow scenario where insufficient input validation allows attackers to exceed allocated memory boundaries. The SITE CHMOD command handler likely fails to properly bounds-check user-supplied parameters before processing them, creating an exploitable condition that can be leveraged through carefully crafted payloads. This type of vulnerability is categorized as CWE-121 in the Common Weakness Enumeration system, which specifically addresses stack-based buffer overflow conditions. The attack vector being remote means that adversaries can exploit this without physical access to the system, making it particularly dangerous for networked environments. The public disclosure of the exploit further amplifies the risk, as it removes the requirement for advanced exploitation techniques and makes the vulnerability accessible to a broader range of threat actors.
The operational impact of this vulnerability extends beyond simple system compromise, as it can potentially allow attackers to gain unauthorized access to sensitive data, modify system configurations, or establish persistent backdoors. The buffer overflow condition may also lead to denial of service scenarios where the server crashes or becomes unresponsive, disrupting legitimate ftp services. Organizations running PCMan FTP Server 2.0.7 are particularly vulnerable since the flaw affects fundamental server functionality and can be exploited by attackers with minimal technical expertise due to the public availability of exploitation methods. This vulnerability particularly impacts environments where ftp servers are exposed to untrusted networks, as it creates multiple attack surfaces for potential exploitation. The remote nature of the attack means that traditional network segmentation measures may not prevent exploitation, requiring more comprehensive security controls.
Mitigation strategies for this vulnerability should prioritize immediate patching of the affected PCMan FTP Server version, as this represents the most effective defense against exploitation. Organizations should implement network segmentation controls to limit access to ftp services and deploy intrusion detection systems to monitor for suspicious SITE CHMOD command usage. The implementation of input validation controls and proper bounds-checking mechanisms should be enforced within the server configuration, though this may require software updates or patches from the vendor. Security monitoring should include detection of anomalous ftp command sequences that may indicate exploitation attempts, particularly focusing on malformed CHMOD parameters. Additionally, organizations should consider implementing application firewalls or web application firewalls that can filter malicious ftp commands before they reach the vulnerable server component. The vulnerability also highlights the importance of regular security assessments and vulnerability scanning to identify similar issues in other ftp server implementations and network services. According to ATT&CK framework, this vulnerability maps to T1071.004 for application layer protocol usage and T1059.007 for command and scripting interpreter, indicating the need for comprehensive defensive measures across multiple attack vectors. Organizations should also consider implementing principle of least privilege controls and regular security audits to reduce the potential impact of successful exploitation attempts.