CVE-2001-1031 in Meteor FTPD
Summary
by MITRE
Directory traversal vulnerability in Meteor FTP 1.0 allows remote attackers to read arbitrary files via (1) a .. (dot dot) in the ls/LIST command, or (2) a ... in the cd/CWD command.
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Analysis
by VulDB Data Team • 05/22/2019
The vulnerability identified as CVE-2001-1031 represents a critical directory traversal flaw within Meteor FTP 1.0, a file transfer protocol implementation that was widely used in early internet infrastructure. This vulnerability stems from inadequate input validation mechanisms within the FTP server's command processing logic, specifically affecting the ls/LIST and cd/CWD commands. The flaw allows remote attackers to manipulate file system paths through specially crafted command sequences containing directory traversal sequences such as .. and ..., effectively bypassing normal file access controls and enabling unauthorized access to arbitrary files on the server's file system.
The technical implementation of this vulnerability leverages the fundamental design weakness in how the FTP server processes directory navigation commands. When the ls/LIST command receives a .. sequence, the server fails to properly sanitize the input path, allowing attackers to traverse upward through the directory structure and access parent directories. Similarly, the cd/CWD command accepts ... sequences that can be exploited to navigate beyond the intended directory boundaries. This represents a classic path traversal vulnerability that aligns with CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory. The vulnerability exists because the application does not adequately validate or sanitize user-supplied input before processing it within the file system context, creating an attack surface where malicious input can manipulate the intended execution path.
The operational impact of this vulnerability extends far beyond simple unauthorized file access, as it provides attackers with the capability to read sensitive system files, configuration data, and potentially compromise the entire server infrastructure. An attacker could exploit this vulnerability to access critical system files such as password databases, configuration files containing database credentials, or application source code that might reveal additional security flaws. The remote nature of the attack means that no local system access is required, making this vulnerability particularly dangerous for internet-facing FTP servers. This aligns with ATT&CK technique T1083, which describes the discovery of system information through directory listing and file enumeration activities. The vulnerability essentially transforms a legitimate file listing function into a reconnaissance tool for attackers seeking to map the server's file system structure and identify valuable targets for further exploitation.
Mitigation strategies for this vulnerability require immediate implementation of proper input validation and sanitization mechanisms within the FTP server software. The most effective approach involves implementing strict path validation that rejects any input containing directory traversal sequences before they can be processed by the file system. This includes implementing comprehensive input filtering that removes or escapes special characters such as .. and ... from user commands. Additionally, the server should enforce proper directory boundary checks that ensure all file operations occur within explicitly defined and restricted directories. Organizations should also implement network segmentation and access control measures to limit exposure of FTP services to only trusted networks, while regularly monitoring for unusual file access patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of validating all user inputs and implementing defense-in-depth strategies, as outlined in security frameworks such as the NIST Cybersecurity Framework and ISO 27001 standards for information security management.