CVE-2013-4301 in MediaWiki
Summary
by MITRE
includes/resourceloader/ResourceLoaderContext.php in MediaWiki 1.19.x before 1.19.8, 1.20.x before 1.20.7, and 1.21.x before 1.21.2 allows remote attackers to obtain sensitive information via a "<" (open angle bracket) character in the lang parameter to w/load.php, which reveals the installation path in an error message.
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Analysis
by VulDB Data Team • 05/24/2021
The vulnerability identified as CVE-2013-4301 represents a critical information disclosure flaw within the MediaWiki content management system that affects multiple version branches including 1.19.x prior to 1.19.8, 1.20.x prior to 1.20.7, and 1.21.x prior to 1.21.2. This vulnerability resides in the ResourceLoaderContext.php file within the includes/resourceloader directory structure of the MediaWiki application. The flaw manifests when a remote attacker submits a malicious lang parameter containing an open angle bracket character to the w/load.php endpoint, which triggers an error message containing the server installation path. This type of information disclosure vulnerability falls under the CWE-200 category, which specifically addresses the exposure of sensitive information to an unauthorized actor. The vulnerability demonstrates characteristics consistent with CWE-497, which deals with the exposure of system-level information, and CWE-312, concerning the exposure of sensitive data within application code. The attack vector operates through the web interface where the ResourceLoader component processes requests for loading CSS and JavaScript resources, making it accessible to any user with network access to the MediaWiki installation.
The technical implementation of this vulnerability stems from inadequate input validation within the ResourceLoaderContext.php file where the lang parameter is processed without proper sanitization or validation of special characters. When an attacker supplies a lang parameter containing the "<" character, the application fails to properly handle this input within the error handling mechanism of the resource loading system. The error message generation process does not adequately sanitize the input before incorporating it into the error output, resulting in the direct revelation of the server filesystem path. This occurs because the application's error handling routine directly echoes user-supplied input without proper HTML escaping or path sanitization, creating a path disclosure scenario that exposes the underlying system structure to potential attackers. The vulnerability is particularly concerning because it provides attackers with precise knowledge of the server's file system layout, which can serve as a foundation for subsequent attacks including directory traversal attempts, privilege escalation, or exploitation of other system-level vulnerabilities.
The operational impact of this vulnerability extends beyond simple information disclosure, creating significant security implications for MediaWiki installations. An attacker who successfully exploits this vulnerability gains access to the complete installation path, which can be used to map the server's directory structure and identify potential weaknesses in the system configuration. This information disclosure can facilitate more sophisticated attacks such as exploiting other vulnerabilities in the same system, conducting targeted attacks against specific file locations, or bypassing security measures that rely on the obscurity of system paths. The exposure of installation paths can also aid in fingerprinting the target environment, allowing attackers to tailor subsequent attacks based on the specific version and configuration of MediaWiki. From an attacker's perspective, this information provides a critical foothold for further reconnaissance and exploitation activities, making it a valuable target for automated scanning tools and manual penetration testing efforts. The vulnerability aligns with ATT&CK technique T1083, which focuses on discovering system information, and T1059, which covers command and scripting interpreter usage, as the disclosed paths can be leveraged to craft more effective attack vectors.
Organizations affected by this vulnerability should implement immediate mitigations to protect their MediaWiki installations from exploitation. The primary recommendation involves upgrading to the patched versions of MediaWiki, specifically versions 1.19.8, 1.20.7, and 1.21.2, which contain the necessary code modifications to properly sanitize input parameters. The fix implemented in these patches involves enhancing the input validation logic within the ResourceLoaderContext.php file to properly sanitize special characters in the lang parameter before any error handling or output processing occurs. Additionally, administrators should consider implementing input filtering at the web application firewall level to block suspicious characters in URL parameters, particularly angle brackets and other special characters that could be used in similar information disclosure attacks. Network-level protections should include monitoring for unusual patterns in requests to the w/load.php endpoint and implementing rate limiting to prevent automated exploitation attempts. Security teams should also conduct thorough audits of their MediaWiki installations to ensure no other similar vulnerabilities exist within the codebase, particularly in components that handle user input and generate error messages. The vulnerability demonstrates the critical importance of proper input sanitization and error handling practices in web applications, reinforcing the need for comprehensive security testing and regular patch management processes.