CVE-2000-0646 in WFTPD
Summary
by MITRE
WFTPD and WFTPD Pro 2.41 allows remote attackers to obtain the real pathname for a file by executing a STATUS (STAT) command while the file is being transferred.
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Analysis
by VulDB Data Team • 10/13/2025
The vulnerability identified as CVE-2000-0646 affects WFTPD and WFTPD Pro version 2.41, representing a significant information disclosure flaw within the File Transfer Protocol implementation. This vulnerability stems from improper handling of the STATUS command during active file transfers, creating a window where sensitive path information can be exposed to remote attackers. The flaw exists in the server-side processing logic that fails to properly sanitize or restrict path information access during concurrent file operations, making it particularly dangerous in environments where file system structure and access patterns are sensitive.
The technical implementation of this vulnerability exploits the specific behavior of the STAT command within the WFTPD server architecture. When a file transfer is in progress, the server maintains internal state information about the current file operations, including path details. The STATUS command, designed for monitoring transfer progress, inadvertently exposes this internal path information through its response mechanism. This occurs because the server does not properly validate or filter the path data before returning it in response to the STAT command, effectively leaking directory structure information to unauthorized users. The vulnerability operates at the protocol level, leveraging legitimate server functionality to bypass normal access controls and information flow restrictions.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with critical path information that can be used for further exploitation. An attacker can construct a series of STATUS commands during active transfers to map the file system structure of the affected server, potentially identifying sensitive files, directories, and access patterns. This information disclosure creates a foundation for more sophisticated attacks, including directory traversal attempts, privilege escalation within the file system, and targeted attacks against specific files or directories. The vulnerability is particularly concerning in multi-user environments where different users have varying levels of access rights, as it can reveal information about files that should remain hidden from unauthorized access.
From a cybersecurity framework perspective, this vulnerability aligns with CWE-200, Information Exposure, and represents a classic case of inadequate input validation and output sanitization within protocol implementations. The flaw demonstrates poor separation of concerns in the server's architecture, where operational state information is not properly isolated from user-facing commands. From an ATT&CK framework perspective, this vulnerability maps to techniques involving reconnaissance and credential access, specifically T1083 (File and Directory Discovery) and T1566 (Phishing for Information), as it enables attackers to gather intelligence about the target system's file structure and access patterns. The vulnerability also reflects broader issues in network service security where protocol-level information leakage can provide attackers with significant advantages in planning subsequent attacks.
Mitigation strategies for this vulnerability require immediate patching of the WFTPD software to version 2.42 or later, which includes proper sanitization of path information in STATUS command responses. Organizations should implement network segmentation to limit access to FTP services and deploy firewall rules that restrict access to these services to trusted networks only. Additionally, administrators should configure the server to disable unnecessary commands or limit their functionality during active transfers. Monitoring for suspicious STATUS command usage and implementing intrusion detection systems that can identify abnormal patterns of file system information access can help detect exploitation attempts. Regular security audits of network services and proper access controls should be implemented to prevent unauthorized access to FTP services and reduce the attack surface. The vulnerability also underscores the importance of proper input validation and output sanitization in protocol implementations, emphasizing the need for security considerations during the design and development phases of network services.