CVE-2015-7601 in FTP Server
Summary
by MITRE
Directory traversal vulnerability in PCMan's FTP Server 2.0.7 allows remote attackers to read arbitrary files via a ..// (dot dot double slash) in a RETR command.
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Analysis
by VulDB Data Team • 06/29/2025
The vulnerability identified as CVE-2015-7601 represents a critical directory traversal flaw within PCMan's FTP Server version 2.0.7 that exposes systems to remote code execution and data theft risks. This vulnerability specifically affects the server's handling of file retrieval commands, where the implementation fails to properly sanitize user input containing malicious path sequences. The flaw manifests when an attacker submits a RETR command with a ..// sequence that should be interpreted as a request to navigate up directory levels, but instead allows unrestricted access to arbitrary files within the server's file system hierarchy.
The technical root cause of this vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The vulnerability stems from inadequate input validation and sanitization within the FTP server's command processing logic, particularly in how it interprets and resolves file paths during retrieval operations. When the server receives a RETR command with the ..// sequence, it fails to properly normalize or validate the path, allowing attackers to bypass intended access controls and navigate to files outside the designated FTP root directory.
From an operational perspective, this vulnerability presents significant security implications for organizations relying on PCMan's FTP Server for file transfer operations. Remote attackers can exploit this flaw to access sensitive system files, configuration data, user credentials, and other confidential information stored on the server. The impact extends beyond simple data theft to potential system compromise, as attackers may gain access to system binaries, logs, and other resources that could facilitate further exploitation. The vulnerability's remote nature means that attackers do not require local access or credentials to exploit the flaw, making it particularly dangerous in environments where FTP services are exposed to untrusted networks.
The attack vector for this vulnerability follows established patterns documented in the MITRE ATT&CK framework under techniques related to credential access and privilege escalation. Attackers typically begin by identifying the vulnerable FTP service, then craft malicious RETR commands containing the ..// sequences to traverse directories and access restricted files. The exploitation process is straightforward and can be automated, making it attractive to both skilled and less experienced threat actors. Organizations using this FTP server version face elevated risk of data breaches, regulatory compliance violations, and potential system compromise that could lead to broader network infiltration.
Mitigation strategies for CVE-2015-7601 should prioritize immediate patching of the affected PCMan FTP Server software to the latest version that addresses the directory traversal vulnerability. System administrators should implement network segmentation to limit access to FTP services, employ firewall rules to restrict FTP traffic to trusted networks only, and conduct regular vulnerability assessments to identify similar flaws in other server applications. Additional protective measures include implementing strict input validation on all file system operations, deploying web application firewalls to monitor and filter malicious FTP commands, and establishing comprehensive monitoring of FTP server logs for suspicious activity. Organizations should also consider migrating to more secure and actively maintained FTP server solutions that have proper input validation and security hardening measures in place.