CVE-2025-4253 in FTP Server
Summary
by MITRE • 05/05/2025
A vulnerability was found in PCMan FTP Server 2.0.7. It has been declared as critical. Affected by this vulnerability is an unknown functionality of the component HASH 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 • 05/05/2025
The vulnerability identified as CVE-2025-4253 represents a critical buffer overflow flaw within PCMan FTP Server version 2.0.7, specifically affecting the HASH command handler component. This type of vulnerability falls under 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 HASH command handler functionality appears to process user input without proper bounds checking, creating an exploitable condition that adversaries can leverage for malicious purposes.
The technical implementation of this vulnerability stems from inadequate input validation within the FTP server's HASH command processing logic. When a remote attacker sends a specially crafted HASH command containing excessive data, the server's buffer handling mechanism fails to properly restrict the input length, resulting in memory overwrite conditions. This flaw operates at the application layer and requires no authentication for exploitation, making it particularly dangerous as it can be triggered through standard FTP client connections. The buffer overflow condition creates opportunities for attackers to execute arbitrary code with the privileges of the FTP server process, potentially leading to complete system compromise.
The operational impact of CVE-2025-4253 extends beyond simple service disruption to encompass full system compromise and data exfiltration capabilities. Remote exploitation allows attackers to gain unauthorized access to systems running vulnerable FTP server versions, potentially enabling them to establish persistent backdoors, escalate privileges, or launch further attacks against internal network resources. The public disclosure of exploitation techniques significantly increases the risk surface, as malicious actors can readily implement automated attack scripts targeting this vulnerability. Organizations utilizing PCMan FTP Server 2.0.7 are particularly vulnerable to coordinated attacks, as the flaw affects core server functionality and provides direct pathways for privilege escalation.
Mitigation strategies for this vulnerability require immediate action including the deployment of official patches from the software vendor, which should address the buffer overflow through proper input validation and bounds checking mechanisms. Network segmentation and firewall rules should be implemented to restrict FTP service access to trusted networks only, while monitoring systems should be configured to detect anomalous HASH command usage patterns. Security teams should consider implementing intrusion detection systems with signatures specifically targeting this vulnerability, and organizations should conduct comprehensive vulnerability assessments to identify all instances of the affected software version. The ATT&CK framework categorizes this vulnerability under T1210 - Exploitation of Remote Services and T1068 - Exploitation for Privilege Escalation, highlighting the multi-stage attack potential that organizations must defend against through layered security approaches. Regular security updates and vulnerability management processes become critical in preventing exploitation of this and similar remote code execution vulnerabilities.