CVE-2000-0126 in IIS
Summary
by MITRE
Sample Internet Data Query (IDQ) scripts in IIS 3 and 4 allow remote attackers to read files via a .. (dot dot) attack.
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Analysis
by VulDB Data Team • 12/29/2024
The vulnerability identified as CVE-2000-0126 represents a critical directory traversal flaw in Microsoft Internet Information Services versions 3 and 4. This weakness specifically affects the Sample Internet Data Query scripts that were included with these server versions, creating an exploitable path traversal condition that allows remote attackers to access arbitrary files on the affected system. The vulnerability stems from inadequate input validation within the IDQ script processing functionality, which fails to properly sanitize user-supplied data before using it to construct file paths. This flaw enables attackers to manipulate the script execution flow by using directory traversal sequences such as ..\.. to navigate outside the intended directory boundaries and access restricted system files.
The technical implementation of this vulnerability leverages the inherent design of the IDQ scripting engine which processes user input directly without proper sanitization or path validation. When an attacker submits a request containing directory traversal sequences, the system processes these inputs without adequate checks, allowing the script to resolve file paths that extend beyond the intended web root directory. This weakness is classified under CWE-22 as "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')" and represents a fundamental flaw in input validation and access control mechanisms. The vulnerability operates at the application layer and can be exploited through HTTP requests that contain specially crafted path traversal sequences, making it particularly dangerous as it can be executed remotely without requiring authentication.
The operational impact of CVE-2000-0126 extends far beyond simple information disclosure, as it provides attackers with the ability to access sensitive system files, configuration data, and potentially execute arbitrary code depending on the system configuration. Attackers can leverage this vulnerability to read system files such as password hashes, configuration files, and other sensitive data that could lead to further system compromise. The vulnerability directly maps to ATT&CK technique T1083 (File and Directory Discovery) and T1566 (Phishing with Malicious Attachments) as it enables adversaries to discover and access files that would normally be restricted. In environments where IIS 3 and 4 were deployed, this vulnerability could result in complete system compromise, particularly when combined with other attack vectors or when the affected server contained sensitive information.
Mitigation strategies for CVE-2000-0126 primarily focus on implementing proper input validation and restricting access to the vulnerable IDQ scripts. Organizations should disable or remove the sample IDQ scripts from production environments, as these were never intended for production use and contain known security vulnerabilities. The recommended approach involves implementing strict path validation mechanisms that prevent directory traversal sequences from being processed, utilizing proper input sanitization techniques, and ensuring that all user-supplied data is validated against a whitelist of acceptable characters and patterns. Additionally, system administrators should consider implementing web application firewalls or security proxies that can detect and block suspicious path traversal attempts. The vulnerability also highlights the importance of following secure coding practices and the principle of least privilege, as demonstrated by the ATT&CK framework's emphasis on preventing unauthorized access to system resources. Organizations should also consider upgrading to supported versions of IIS that have addressed these vulnerabilities and implemented proper security controls to prevent similar issues in the future.