CVE-2000-0876 in wftpd
Summary
by MITRE
WFTPD and WFTPD Pro 2.41 RC12 allows remote attackers to obtain the full pathname of the server via a "%C" command, which generates an error message that includes the pathname.
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Analysis
by VulDB Data Team • 05/09/2019
The vulnerability identified as CVE-2000-0876 represents a critical information disclosure flaw in WFTPD and WFTPD Pro versions 2.41 RC12. This vulnerability resides within the File Transfer Protocol implementation and specifically targets the error handling mechanisms of the software. The flaw manifests when a remote attacker sends a specially crafted "%C" command to the FTP server, which triggers an error message generation process that inadvertently exposes sensitive system path information to unauthorized parties. This type of vulnerability falls under the category of information disclosure as defined by the Common Weakness Enumeration framework with CWE-200, which encompasses weaknesses that result in the exposure of sensitive information to an attacker.
The technical exploitation of this vulnerability occurs through the manipulation of the FTP protocol interface where the "%C" command sequence causes the server to process an error condition that includes the absolute file path in the error response. This occurs because the FTP server does not properly sanitize or filter the input parameters before incorporating them into error messages, creating a path traversal information disclosure scenario. The vulnerability is particularly dangerous as it provides attackers with precise knowledge of the server's directory structure, which can serve as a foundation for further exploitation attempts including directory traversal attacks, file system enumeration, and potential privilege escalation activities.
The operational impact of this vulnerability extends beyond simple information disclosure, as it significantly weakens the overall security posture of systems running affected WFTPD versions. When attackers obtain the full pathname of the server, they gain valuable reconnaissance information that can be used to map the file system structure and identify potential targets for more sophisticated attacks. This vulnerability aligns with ATT&CK technique T1083 (File and Directory Discovery) as it enables adversaries to gather detailed information about the target system's file structure without requiring direct access or authentication. The exposure of system paths can also facilitate other attack vectors such as path traversal exploits, where attackers might attempt to access restricted files or directories that would otherwise be protected by proper access controls.
Organizations running affected WFTPD software face significant risks from this vulnerability, as it provides attackers with the exact directory structure of their servers. The vulnerability is particularly concerning in environments where the FTP server serves as a primary file access mechanism, as it can expose sensitive application directories, configuration files, and potentially user data. The lack of proper input validation and error handling in the software implementation creates a persistent security risk that can be exploited by any remote attacker with access to the FTP service. Security teams should consider this vulnerability as a critical threat that requires immediate remediation through software updates or patches provided by the vendor, as well as network segmentation and access control measures to limit exposure. The vulnerability demonstrates the importance of proper error handling practices and input validation in server applications, as even seemingly benign error conditions can expose critical system information to unauthorized parties.