CVE-2015-6731 in MediaWiki
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in the SemanticForms extension for MediaWiki allow remote attackers to inject arbitrary web script or HTML via a (1) section_*, (2) template_*, (3) label_*, or (4) new_template parameter to Special:CreateForm or (5) target or (6) alt_form parameter to Special:FormEdit.
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Analysis
by VulDB Data Team • 03/10/2018
The CVE-2015-6731 vulnerability represents a critical cross-site scripting flaw within the SemanticForms extension for MediaWiki, a widely deployed wiki software platform used by organizations ranging from educational institutions to government agencies. This vulnerability exists in the form processing mechanisms of the extension, specifically targeting parameters used in two key special pages: Special:CreateForm and Special:FormEdit. The flaw allows remote attackers to execute malicious scripts in the context of victim browsers, potentially leading to session hijacking, data theft, or full compromise of user accounts. The vulnerability affects versions of MediaWiki that incorporate the SemanticForms extension, making it a widespread concern for wiki administrators and security professionals managing collaborative content platforms.
The technical implementation of this vulnerability stems from insufficient input validation and output sanitization within the SemanticForms extension's parameter handling logic. Attackers can exploit this weakness by crafting malicious payloads in specific parameter names including section_, template_, label_*, new_template, target, and alt_form parameters. These parameters are processed without adequate sanitization when users navigate to Special:CreateForm or Special:FormEdit pages, creating opportunities for persistent XSS attacks. The vulnerability operates at the application layer, requiring no privileged access or authentication to exploit, which significantly increases its attack surface and potential impact. This flaw directly maps to CWE-79, which defines cross-site scripting vulnerabilities as the injection of malicious code into web applications, and aligns with ATT&CK technique T1566.001 for initial access through spearphishing attachments or links.
The operational impact of CVE-2015-6731 extends beyond simple script execution, as it can enable attackers to perform sophisticated attacks against authenticated users. When exploited, the vulnerability allows adversaries to steal session cookies, redirect users to malicious sites, or inject malicious content that can persist across multiple user sessions. The affected parameters are commonly used in legitimate wiki operations, making the attack vectors particularly insidious as they can appear to originate from trusted sources within the wiki environment. Organizations relying on MediaWiki for collaborative documentation, knowledge management, or internal communication platforms face significant risk from this vulnerability, as it can be leveraged to compromise sensitive information or disrupt collaborative workflows. The persistent nature of XSS vulnerabilities means that once exploited, the malicious code can continue to affect users until the underlying vulnerability is patched or the affected parameters are properly sanitized.
Mitigation strategies for CVE-2015-6731 require immediate action from system administrators and security teams managing affected MediaWiki installations. The most effective solution involves applying the official patches released by the MediaWiki project and the SemanticForms extension maintainers, which typically include enhanced input validation and output sanitization mechanisms for the affected parameters. Organizations should also implement web application firewalls with XSS detection capabilities as an additional defensive layer, though this should not replace proper patching. Security teams should conduct comprehensive vulnerability assessments to identify all affected MediaWiki instances and ensure proper parameter validation across all extension modules. The remediation process should include thorough testing to prevent regression issues while implementing the security fixes, and organizations should consider implementing content security policies to further mitigate potential exploitation scenarios. Regular security monitoring and patch management procedures should be strengthened to prevent similar vulnerabilities from emerging in other MediaWiki extensions or custom modifications.