CVE-2000-0039 in Search Intranet
Summary
by MITRE
AltaVista search engine allows remote attackers to read files above the document root via a .. (dot dot) in the query.cgi CGI program.
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Analysis
by VulDB Data Team • 01/26/2025
The vulnerability described in CVE-2000-0039 represents a classic directory traversal attack that exploited a critical flaw in the AltaVista search engine's query.cgi CGI program. This vulnerability allowed remote attackers to access files outside the intended document root directory by manipulating the query parameters with directory traversal sequences. The flaw specifically manifested when the application failed to properly validate or sanitize user input before processing file paths, creating an opportunity for malicious actors to navigate the file system beyond the designated web root. This type of vulnerability falls under the category of improper input validation and is classified as CWE-22, which addresses improper limitation of a pathname to a restricted directory. The attack vector was particularly dangerous as it required no authentication or special privileges, making it accessible to any remote user who could interact with the search engine's CGI interface.
The technical implementation of this vulnerability relied on the exploitation of the .. (dot dot) traversal sequence that is commonly used in file systems to move up one directory level. When the query.cgi program processed user input without proper sanitization, attackers could append sequences like ../../etc/passwd to their search queries, effectively allowing them to read sensitive system files that should have been protected from web access. The vulnerability was particularly concerning because it could potentially expose not only system configuration files but also application-specific data, user information, and other sensitive resources stored on the server. This weakness directly violated fundamental security principles of least privilege and proper access control, as the application failed to enforce directory boundaries that should have prevented such arbitrary file access.
The operational impact of this vulnerability was significant for organizations relying on the AltaVista search engine, as it provided attackers with unauthorized access to potentially sensitive information stored on the server. Depending on the server configuration and the privileges of the web application process, attackers might have been able to read system files, application source code, database credentials, or user data that was not intended for public access. The vulnerability also posed risks to the overall system integrity, as it could potentially serve as a stepping stone for further attacks or provide attackers with information needed to exploit other system weaknesses. This type of vulnerability is categorized under the ATT&CK technique T1083, which involves discovering system information through directory listing and file access methods, making it particularly relevant for threat actors seeking to map the target environment and identify additional attack vectors.
Mitigation strategies for this vulnerability required immediate implementation of input validation and sanitization measures within the affected CGI application. Organizations needed to ensure that all user-supplied input was properly validated and that directory traversal sequences were either rejected or properly encoded before being processed by the application. The fix typically involved implementing proper path validation logic that would detect and block attempts to navigate above the designated document root directory. Security practitioners should have implemented proper access controls, ensuring that the web application ran with minimal privileges and that file system access was restricted to only necessary directories. Additionally, regular security audits and code reviews became essential practices to identify similar vulnerabilities in other applications, as this type of flaw was common across many web applications that failed to properly validate file paths. The vulnerability highlighted the importance of following secure coding practices and implementing proper input validation as fundamental security controls to prevent directory traversal attacks.