CVE-2016-6331 in MediaWiki
Summary
by MITRE
ApiParse in MediaWiki before 1.23.15, 1.26.x before 1.26.4, and 1.27.x before 1.27.1 allows remote attackers to bypass intended per-title read restrictions via a parse action to api.php.
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Analysis
by VulDB Data Team • 12/01/2022
The vulnerability identified as CVE-2016-6331 represents a critical access control flaw in MediaWiki's API parsing functionality that affects multiple version branches including 1.23.14 and earlier, 1.26.3 and earlier, and 1.27.0 and earlier releases. This issue resides within the ApiParse component of MediaWiki's application programming interface which handles the parsing of wiki markup content through the api.php endpoint. The flaw enables remote attackers to circumvent the intended read restrictions that are typically enforced on individual wiki pages, effectively allowing unauthorized access to content that should remain protected or restricted based on user permissions or page-specific access controls. The vulnerability specifically targets the parse action functionality within the MediaWiki API, which is designed to convert wiki markup into HTML for display purposes while maintaining proper access controls.
The technical implementation of this vulnerability stems from inadequate validation of user permissions during the parse action execution process. When a user requests to parse content through the api.php endpoint, the system should verify that the requesting user has appropriate read permissions for the specific title being parsed. However, the flaw exists in the permission checking mechanism where the system fails to properly enforce the intended per-title access restrictions. This occurs because the ApiParse function does not adequately validate whether the authenticated user possesses the necessary privileges to read the target page content before executing the parsing operation. The vulnerability manifests when an attacker can manipulate the parse action parameters to request parsing of restricted pages, bypassing the normal access control checks that would typically prevent such operations. This weakness creates a pathway for attackers to extract content that should be protected by page-level permissions, effectively undermining the entire access control framework of the MediaWiki system.
The operational impact of CVE-2016-6331 extends beyond simple information disclosure, as it represents a fundamental breakdown in the security model of MediaWiki installations. Attackers can exploit this vulnerability to access sensitive information that is protected by read restrictions, potentially including confidential wiki content, private discussions, or restricted documentation that should only be accessible to authorized users. The implications are particularly severe for organizations that rely on MediaWiki for internal documentation, knowledge management, or collaborative platforms where different user groups require varying levels of access to different content. The vulnerability affects both the content presentation layer and the underlying access control mechanisms, making it a significant concern for any MediaWiki deployment that implements page-level permissions. Organizations using affected versions may experience unauthorized access to protected content, potential data breaches, and violations of information security policies that govern access to sensitive wiki materials.
Mitigation strategies for CVE-2016-6331 primarily focus on immediate software upgrades to patched versions of MediaWiki, specifically versions 1.23.15, 1.26.4, and 1.27.1 or later. System administrators should prioritize updating their MediaWiki installations to ensure the vulnerability is resolved at the source. Additionally, organizations can implement temporary network-level restrictions to limit access to the api.php endpoint, though this approach provides only partial protection and should not replace proper software updates. Security monitoring should be enhanced to detect unusual API access patterns that might indicate exploitation attempts, particularly around parse actions targeting restricted pages. The vulnerability aligns with CWE-284, which addresses improper access control in software systems, and relates to ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting, as attackers may exploit this vulnerability to gain unauthorized access to protected content. Organizations should also review their existing access control policies and ensure that proper user authentication and authorization mechanisms are in place to minimize the potential impact of such vulnerabilities. Regular security assessments and vulnerability scanning should be implemented to identify and address similar access control weaknesses in other components of the wiki platform.