CVE-2001-0480 in FTP Server
Summary
by MITRE
Directory traversal vulnerability in Alex s FTP Server 0.7 allows remote attackers to read arbitrary files via a ... (modified dot dot) in the (1) GET or (2) CD commands.
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Analysis
by VulDB Data Team • 03/24/2017
The CVE-2001-0480 vulnerability represents a critical directory traversal flaw in Alex s FTP Server version 0.7 that fundamentally compromises file system security through improper input validation. This vulnerability specifically affects the GET and CD commands within the FTP server implementation, allowing remote attackers to manipulate path resolution mechanisms and access files outside the intended directory structure. The flaw exploits the server's failure to properly sanitize user-supplied path parameters, enabling malicious actors to construct arbitrary file paths using directory traversal sequences that bypass normal access controls.
The technical implementation of this vulnerability stems from inadequate input validation and path resolution logic within the FTP server's command processing routines. When users submit GET or CD commands with specially crafted directory traversal sequences such as "...", the server fails to properly normalize or validate these paths before attempting file system operations. This allows attackers to navigate beyond the server's intended file system boundaries and access sensitive files that should remain protected. The vulnerability operates at the application layer and can be exploited without requiring authentication, making it particularly dangerous in unsecured network environments where FTP services are exposed to external networks.
The operational impact of CVE-2001-0480 extends beyond simple unauthorized file access, potentially enabling attackers to retrieve system configuration files, user credentials, application source code, and other sensitive data stored on the affected server. This vulnerability directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The attack vector leverages the fundamental weakness in how the FTP server handles relative path references, allowing attackers to manipulate file system operations through carefully crafted command sequences. Such vulnerabilities are categorized under ATT&CK technique T1213.002 for data from information repositories, as they enable unauthorized access to stored information through compromised file system interfaces.
Security practitioners should implement immediate mitigations including updating to patched versions of Alex s FTP Server, implementing proper input validation and sanitization for all user-supplied path parameters, and configuring firewall rules to restrict FTP service access to trusted networks only. Network segmentation and access control lists should be deployed to limit exposure of FTP services to unnecessary network segments. Additionally, regular security audits of file system access controls and monitoring for suspicious FTP activity should be implemented to detect potential exploitation attempts. Organizations should also consider migrating to more secure file transfer protocols such as SFTP or FTPS that provide better authentication and encryption mechanisms to prevent similar vulnerabilities from affecting their infrastructure.