CVE-2002-1544 in Personal FTP Server
Summary
by MITRE
Directory traversal vulnerability in CooolSoft Personal FTP Server 2.24 allows remote attackers to read or modify arbitrary files via .. (dot dot) sequences in the commands (1) LIST (ls), (2) mkdir, (3) put, or (4) get.
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Analysis
by VulDB Data Team • 03/13/2017
The vulnerability described in CVE-2002-1544 represents a critical directory traversal flaw within the CooolSoft Personal FTP Server version 2.24 that exposes the system to remote exploitation. This weakness allows attackers to manipulate file system access through carefully crafted command sequences containing dot-dot notation that should normally be restricted. The vulnerability specifically affects four fundamental FTP commands: LIST (ls), mkdir, put, and get, making it particularly dangerous as it can be leveraged for both information disclosure and unauthorized modification of system files.
The technical implementation of this vulnerability stems from inadequate input validation within the FTP server's command processing logic. When users submit commands containing .. sequences, the server fails to properly sanitize these inputs before executing file system operations. This lack of proper validation creates an opportunity for attackers to navigate beyond the intended directory structure and access files that should remain protected. The flaw operates at the application layer where the server interprets user commands without sufficient boundary checking, allowing malicious path manipulation to occur.
From an operational perspective, this vulnerability poses significant risk to organizations relying on the affected FTP server software. Remote attackers can exploit this weakness to read sensitive configuration files, system binaries, or user data that may contain credentials, personal information, or proprietary content. The ability to perform directory traversal through the put command is particularly concerning as it allows attackers to upload malicious files to arbitrary locations on the server, potentially leading to complete system compromise. The vulnerability's impact extends beyond simple file access as it can facilitate further exploitation through privilege escalation or lateral movement within the network.
Security professionals should consider this vulnerability in relation to CWE-22 which specifically addresses improper limitation of a pathname to a restricted directory, also known as path traversal or directory traversal. The ATT&CK framework categorizes this type of vulnerability under T1078 Valid Accounts and T1566 Phishing, as attackers often leverage such flaws to establish persistent access or move laterally within compromised systems. The vulnerability's age and the fact that it affects a personal FTP server indicates that it likely represents an unpatched legacy system that organizations may have overlooked during security assessments.
Mitigation strategies for this vulnerability should focus on immediate software updates and patches provided by the vendor, though given the age of this specific version, organizations may need to consider migrating to more modern FTP server implementations. Network segmentation and access controls should be implemented to limit exposure of FTP services to trusted networks only. Additionally, implementing proper input validation and sanitization measures within the FTP server configuration can help prevent similar issues from occurring in other applications. Organizations should also conduct thorough vulnerability assessments to identify any other instances of similar path traversal flaws within their infrastructure that may have been overlooked.