CVE-2001-0294 in FTP Server
Summary
by MITRE
Directory traversal vulnerability in TYPSoft FTP Server 0.85 allows remote attackers to read arbitrary files via (1) a .. (dot dot) in a GET command, or (2) a ... in a CWD command.
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Analysis
by VulDB Data Team • 06/25/2021
The CVE-2001-0294 vulnerability represents a critical directory traversal flaw in TYPSoft FTP Server version 0.85 that exposes fundamental security weaknesses in file access controls. This vulnerability operates at the core of network protocol implementation where proper input validation fails to prevent malicious path manipulation attempts. The flaw specifically targets the server's handling of user commands that navigate file system directories, creating an exploitable condition where remote attackers can bypass normal access controls and retrieve unauthorized files from the underlying operating system. The vulnerability exists due to insufficient sanitization of user-supplied input parameters that are directly incorporated into file system operations without proper validation or restriction mechanisms.
The technical implementation of this vulnerability stems from the server's inadequate parsing and validation of directory navigation commands. When a remote attacker sends a GET command containing .. (dot dot) sequences or a CWD command with ... (three dots) patterns, the server processes these inputs without proper boundary checking or path normalization. This allows the attacker to traverse up the directory tree and access files outside the intended server directory structure. The vulnerability is classified as a path traversal attack under CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory. The flaw demonstrates a classic lack of input sanitization where the server fails to validate that requested file paths remain within the designated server root directory. This type of vulnerability enables attackers to access sensitive system files, configuration data, and potentially user information that should remain protected within the server's designated file hierarchy.
The operational impact of CVE-2001-0294 extends beyond simple unauthorized file access to encompass broader system compromise potential. Attackers can leverage this vulnerability to read system configuration files, user credentials stored in plain text, application source code, and other sensitive data that may contain system vulnerabilities or authentication information. The remote nature of the attack means that no local system access is required, making this vulnerability particularly dangerous as it can be exploited from anywhere on the network. This vulnerability aligns with ATT&CK technique T1005 which covers data from local system, and T1071.004 which involves application layer protocol traffic. The impact is significant because FTP servers typically contain sensitive organizational data, and unauthorized access to these systems can lead to data breaches, system compromise, and potential lateral movement within network environments. The vulnerability also represents a failure in the principle of least privilege where the server grants excessive file system access based on user input without proper access control enforcement.
Mitigation strategies for CVE-2001-0294 require immediate implementation of proper input validation and path normalization techniques. Organizations should upgrade to patched versions of TYPSoft FTP Server or migrate to more modern and secure FTP implementations that properly handle directory traversal attempts. The recommended approach involves implementing strict input filtering that rejects or normalizes path traversal sequences before they are processed by the server. Security controls should include proper path validation that ensures all file system operations occur within predefined boundaries and that directory navigation commands are sanitized to prevent upward path traversal. Network segmentation and firewall rules should limit access to FTP services to only authorized users and systems. Additionally, implementing proper logging and monitoring of FTP access patterns can help detect exploitation attempts. This vulnerability highlights the importance of input validation as a fundamental security control, aligning with security frameworks that emphasize the need for proper sanitization of all user inputs. Organizations should also consider implementing intrusion detection systems that can identify and alert on suspicious FTP command sequences that match known attack patterns for directory traversal exploits.