CVE-2012-4378 in MediaWiki
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in MediaWiki before 1.18.5 and 1.19.x before 1.19.2, when unspecified JavaScript gadgets are used, allow remote attackers to inject arbitrary web script or HTML via the userlang parameter to w/index.php.
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Analysis
by VulDB Data Team • 04/12/2021
The vulnerability described in CVE-2012-4378 represents a critical cross-site scripting flaw affecting MediaWiki installations prior to specific version releases. This vulnerability specifically targets the handling of the userlang parameter within the w/index.php endpoint, creating a pathway for remote attackers to execute malicious web scripts or HTML code within the context of affected users' browsers. The issue manifests when JavaScript gadgets are enabled and utilized within the MediaWiki environment, making it particularly dangerous for wikis that support user-generated content and gadget functionality.
The technical root cause of this vulnerability lies in insufficient input validation and sanitization of the userlang parameter. When users provide input through this parameter, the MediaWiki application fails to properly escape or filter the data before incorporating it into dynamic web page content. This allows attackers to inject malicious payloads that execute in the browser context of other users who visit pages containing the compromised content. The vulnerability operates under CWE-79 which specifically addresses cross-site scripting flaws, where improper neutralization of input during web page generation creates opportunities for attackers to execute arbitrary scripts in user browsers.
From an operational perspective, this vulnerability presents significant risks to wiki communities and organizations relying on MediaWiki platforms. Attackers could exploit this flaw to steal user sessions, redirect visitors to malicious sites, deface wiki content, or harvest sensitive information from authenticated users. The impact extends beyond individual page compromise to potentially affecting entire wiki communities, especially those with high user engagement and trusted gadget configurations. The vulnerability affects both the 1.18.x series before 1.18.5 and the 1.19.x series before 1.19.2, indicating it was present across multiple stable release lines and likely affected numerous organizations and institutions using MediaWiki for collaborative documentation and knowledge management.
The attack vector for this vulnerability follows typical XSS exploitation patterns where an attacker crafts a malicious URL containing the userlang parameter with injected script payloads. When a victim visits this URL, the MediaWiki application processes the parameter without proper sanitization, executing the malicious code within the victim's browser context. This aligns with ATT&CK technique T1566 which covers social engineering attacks including spearphishing with a payload, where the malicious injection occurs through web application interfaces. Organizations using MediaWiki should prioritize immediate patching to version 1.18.5 or 1.19.2 respectively, as these releases contain the necessary input validation fixes. Additional mitigations include implementing proper content security policies, disabling unnecessary gadget functionality where possible, and conducting regular security assessments of web applications to identify similar input validation weaknesses.
Security practitioners should note that this vulnerability demonstrates the importance of input validation across all user-controllable parameters in web applications, particularly those that dynamically generate content. The issue highlights the need for comprehensive security testing including dynamic analysis of web application inputs and outputs, as well as regular security updates to address known vulnerabilities in widely-used software platforms. Organizations maintaining MediaWiki installations must establish robust patch management processes to ensure timely deployment of security fixes and maintain awareness of security advisories from software vendors and security communities.