CVE-2000-0079 in CERN httpd
Summary
by MITRE
The W3C CERN httpd HTTP server allows remote attackers to determine the real pathnames of some commands via a request for a nonexistent URL.
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Analysis
by VulDB Data Team • 10/19/2025
The vulnerability identified as CVE-2000-0079 affects the W3C CERN httpd HTTP server implementation, representing a classic information disclosure flaw that exposes underlying system path structures to remote attackers. This vulnerability stems from the server's inadequate handling of requests for nonexistent URLs, where the server inadvertently reveals internal directory structures and command paths through its error response mechanisms. The flaw operates at the application layer of the network stack, specifically within the HTTP protocol implementation where the server processes and responds to client requests. When an attacker submits a request for a non-existent resource, the server's response contains sufficient information to allow an attacker to map out parts of the underlying filesystem structure, potentially exposing sensitive directory paths and command locations.
The technical implementation of this vulnerability resides in the server's error handling routines and path resolution mechanisms. The W3C CERN httpd server, while designed as an early web server implementation, contained flawed logic in how it processed malformed requests and generated error responses. When encountering a nonexistent URL, the server would include path information in its error messages that could be exploited to determine the actual filesystem layout of the server. This type of vulnerability falls under CWE-200, which specifically addresses information exposure, and represents a precursor to more sophisticated path traversal and information disclosure attacks that would later become prevalent in web server security. The vulnerability is particularly concerning because it provides attackers with foundational knowledge about the target system's architecture without requiring any authentication or privileged access.
The operational impact of CVE-2000-0079 extends beyond simple information disclosure, as the revealed path information can serve as a critical reconnaissance step for more advanced attacks. An attacker who successfully exploits this vulnerability gains knowledge about the server's internal structure, including potential command locations and directory hierarchies that could be leveraged in subsequent attacks. This information disclosure can facilitate path traversal attacks, where attackers might use the revealed paths to access files outside the intended web root directory. The vulnerability also aligns with ATT&CK technique T1213, which covers data from information repositories, as it provides attackers with valuable system information that can be used for further exploitation. The exposure of real pathnames creates potential attack vectors for directory traversal, privilege escalation, and other attacks that rely on understanding the target system's filesystem structure. Organizations using this vulnerable server implementation face significant risk as attackers can use this information to plan more sophisticated attacks, including potential exploitation of other vulnerabilities that may exist in the revealed paths.
Mitigation strategies for this vulnerability involve both immediate and long-term approaches to address the root cause. The most direct solution requires updating to a patched version of the W3C CERN httpd server or migrating to a more modern, supported web server implementation that properly handles error responses without exposing system path information. Organizations should implement proper error handling that returns generic error messages to clients while logging detailed information internally for administrative purposes. The implementation of input validation and sanitization measures can prevent malformed requests from triggering the vulnerable code paths. Additionally, security configurations should be reviewed to ensure that error responses do not contain sensitive system information, and access controls should be implemented to limit the exposure of internal server details. This vulnerability highlights the importance of secure coding practices and proper error handling in web server implementations, as it demonstrates how seemingly benign error responses can provide attackers with critical system information that undermines overall security posture. The vulnerability also underscores the necessity of regular security assessments and updates to prevent exploitation of known weaknesses in legacy software implementations.