CVE-2011-0537 in MediaWiki
Summary
by MITRE
Multiple directory traversal vulnerabilities in (1) languages/Language.php and (2) includes/StubObject.php in MediaWiki 1.8.0 and other versions before 1.16.2, when running on Windows and possibly Novell Netware, allow remote attackers to include and execute arbitrary local PHP files via vectors related to a crafted language file and the Language::factory function.
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Analysis
by VulDB Data Team • 10/13/2021
The vulnerability identified as CVE-2011-0537 represents a critical directory traversal flaw affecting MediaWiki versions prior to 1.16.2, specifically impacting installations running on Windows and potentially Novell Netware operating systems. This vulnerability stems from improper input validation within the language handling mechanisms of the MediaWiki platform, creating a pathway for remote attackers to execute arbitrary PHP code through carefully crafted language files. The affected components include the languages/Language.php and includes/StubObject.php files, which together form a critical part of the application's internationalization and object instantiation processes. The vulnerability manifests when the Language::factory function processes user-supplied language identifiers without adequate sanitization, allowing attackers to manipulate file paths and access unauthorized local resources.
The technical exploitation of this vulnerability involves leveraging directory traversal sequences to bypass normal file access controls and include local PHP files that would typically be restricted from external access. Attackers can craft malicious language identifiers that, when processed by the Language::factory function, result in the inclusion of arbitrary local files, potentially leading to remote code execution. This flaw operates under CWE-22, which categorizes directory traversal vulnerabilities as a fundamental weakness in input validation. The vulnerability's impact is particularly severe on Windows systems where the file system behavior and path resolution mechanisms differ from Unix-like systems, creating additional attack surface. The issue is exacerbated by the fact that MediaWiki's language handling system is designed to dynamically load language files based on user input, making the attack vector particularly insidious as it can be triggered through normal application usage patterns.
The operational impact of CVE-2011-0537 extends beyond simple code execution to encompass complete system compromise when attackers can manipulate the application's behavior through language file inclusion. Successful exploitation allows attackers to execute arbitrary PHP code with the privileges of the web server process, potentially enabling them to access sensitive data, modify application behavior, or establish persistent access to the compromised system. The vulnerability affects not only the MediaWiki application itself but can also impact the underlying hosting environment, potentially compromising other applications running on the same server. This represents a significant concern for organizations relying on MediaWiki for content management, as the vulnerability can be exploited without requiring authentication and can be triggered through standard web browser interactions. The attack surface is particularly wide given that language selection is a common user interaction point in web applications, making this vulnerability highly exploitable in real-world scenarios.
Mitigation strategies for CVE-2011-0537 primarily focus on immediate patching of affected MediaWiki installations to version 1.16.2 or later, which contains the necessary fixes for the directory traversal vulnerability. Organizations should also implement input validation measures at the application level to sanitize all language identifiers and prevent path traversal sequences from being processed. Network-level protections including web application firewalls and intrusion detection systems can help detect and block exploitation attempts, while proper file system permissions should be enforced to limit access to sensitive application files. The vulnerability's classification under ATT&CK technique T1190 - Exploit Public-Facing Application, highlights the need for comprehensive security monitoring and incident response capabilities. Additionally, system administrators should conduct thorough security assessments of all MediaWiki installations and ensure that proper access controls are in place to prevent unauthorized modification of language files. Regular security updates and patch management processes should be implemented to prevent similar vulnerabilities from being introduced in future versions of the application.