CVE-2025-3678 in FTP Server
Summary
by MITRE • 04/16/2025
A vulnerability, which was classified as critical, has been found in PCMan FTP Server 2.0.7. This issue affects some unknown processing of the component HELP Command Handler. The manipulation leads to buffer overflow. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 05/13/2025
The vulnerability identified as CVE-2025-3678 represents a critical buffer overflow condition within PCMan FTP Server version 2.0.7, specifically within the HELP Command Handler component. This type of vulnerability falls under the Common Weakness Enumeration category CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The flaw exists in the server's handling of FTP HELP commands, which are typically used by clients to retrieve information about available commands from the FTP server.
The technical implementation of this vulnerability stems from improper input validation and memory management within the HELP command processing module. When the FTP server receives a malformed HELP command with excessive input data, the application fails to properly bound-check the input before copying it into a fixed-size buffer. This allows an attacker to overflow the allocated buffer space and potentially overwrite adjacent memory segments including return addresses, function pointers, or other critical control data structures. The remote exploitability of this vulnerability means that an attacker can trigger the buffer overflow without requiring physical access to the system, making it particularly dangerous in networked environments.
The operational impact of this critical vulnerability extends beyond simple denial of service conditions to potentially enable remote code execution. An attacker who successfully exploits this buffer overflow could gain arbitrary code execution privileges on the affected FTP server, potentially allowing full system compromise, data exfiltration, or establishment of persistent backdoors. The disclosure of exploit code increases the likelihood of widespread exploitation across vulnerable installations, as demonstrated by similar vulnerabilities in FTP server implementations that have been weaponized in the wild. Organizations running PCMan FTP Server 2.0.7 are particularly at risk since the vulnerability affects core protocol handling functionality that is essential for normal FTP operations.
Mitigation strategies for CVE-2025-3678 should prioritize immediate patching of affected systems, as the vulnerability has been publicly disclosed and is actively exploitable. System administrators should upgrade to the latest version of PCMan FTP Server that addresses this specific buffer overflow condition, while also implementing network-level restrictions such as firewall rules that limit FTP server access to trusted networks only. Additional defensive measures include implementing intrusion detection systems to monitor for suspicious FTP command patterns, disabling unnecessary FTP services, and conducting comprehensive vulnerability assessments of all networked systems that may be running vulnerable FTP server software. The ATT&CK framework categorizes this vulnerability under T1190 - Exploit Public-Facing Application, highlighting the importance of securing externally accessible FTP services and implementing proper network segmentation to limit potential attack surface. Organizations should also consider migrating from legacy FTP protocols to more secure alternatives such as SFTP or FTPS to reduce exposure to similar vulnerabilities in the future.