CVE-2002-1354 in FTP Server
Summary
by MITRE
Directory traversal vulnerability in TYPSoft FTP Server 0.99.8 allows local users to list the contents of arbitrary directories via a ... (dot dot dot) in the cd/CWD command.
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Analysis
by VulDB Data Team • 06/04/2019
The directory traversal vulnerability identified as CVE-2002-1354 affects TYPSoft FTP Server version 0.99.8 and represents a critical security flaw that enables local attackers to bypass normal file system access controls. This vulnerability specifically targets the command handling mechanism within the FTP server implementation, where the server fails to properly validate directory change commands. The flaw manifests when the cd or CWD command receives a path containing the ... sequence, which should normally be rejected or properly sanitized by the server's input validation routines. This particular vulnerability falls under the CWE-22 category of Improper Limitation of a Pathname to a Restricted Directory, commonly known as Path Traversal or Directory Traversal attacks. The attack vector is particularly concerning because it allows an attacker to enumerate and potentially access files outside the intended directory structure that the FTP server is configured to serve.
The technical implementation of this vulnerability stems from inadequate input sanitization within the FTP server's command processing logic. When a local user submits a cd or CWD command containing the ... sequence, the server does not properly canonicalize or validate the path before executing the directory change operation. This allows the attacker to traverse up the directory hierarchy beyond the server's intended access boundaries. The vulnerability is classified as a local privilege escalation vector since it requires local system access to exploit, but the impact remains significant as it can potentially expose sensitive system files, configuration data, and user information that should remain protected. The attack pattern aligns with the MITRE ATT&CK framework's technique T1083 (File and Directory Discovery) and T1566 (Phishing for Information) when combined with other attack vectors. The server's failure to properly implement path validation creates a scenario where legitimate directory navigation commands can be manipulated to access unauthorized file system locations.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially lead to complete system compromise when combined with other exploitation techniques. Local attackers who can submit FTP commands can leverage this vulnerability to discover system configuration files, user credentials stored in accessible locations, and potentially sensitive data that should remain isolated from unauthorized access. The vulnerability affects the fundamental security model of the FTP server by undermining the principle of least privilege, allowing attackers to bypass directory access controls that are typically enforced by the operating system's file system permissions. This flaw represents a critical weakness in the server's security architecture and can be particularly dangerous in environments where FTP servers are used to serve sensitive data or where local system access is not strictly controlled. The vulnerability can also serve as a stepping stone for more sophisticated attacks, as it provides an attacker with additional information about the system's file structure and potentially reveals other security weaknesses.
Mitigation strategies for CVE-2002-1354 should focus on immediate patching of the affected TYPSoft FTP Server version, as this represents the most effective solution to eliminate the vulnerability. Organizations should implement strict input validation mechanisms that properly sanitize all user-supplied path data before processing, particularly for commands that manipulate directory navigation. The implementation of proper path canonicalization routines that resolve and validate directory paths against a predefined safe directory structure can prevent this type of attack. System administrators should also consider implementing additional security controls such as network segmentation, access control lists, and monitoring for suspicious FTP command sequences. From a defensive perspective, the vulnerability highlights the importance of maintaining up-to-date software versions and implementing robust input validation practices throughout the application stack. The attack pattern described in this vulnerability is consistent with common exploitation techniques that have been documented in various security advisories and represents a classic example of why proper security testing and code review are essential for network services. Organizations should also consider implementing intrusion detection systems that can identify and alert on suspicious FTP command patterns that may indicate attempts to exploit directory traversal vulnerabilities.