CVE-2015-8622 in MediaWiki
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in MediaWiki before 1.23.12, 1.24.x before 1.24.5, 1.25.x before 1.25.4, and 1.26.x before 1.26.1, when is configured with a relative URL, allows remote authenticated users to inject arbitrary web script or HTML via wikitext, as demonstrated by a wikilink to a page named "javascript:alert('XSS!')."
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Analysis
by VulDB Data Team • 11/14/2022
The CVE-2015-8622 vulnerability represents a critical cross-site scripting flaw in MediaWiki platforms across multiple version ranges, including versions prior to 1.23.12, 1.24.x before 1.24.5, 1.25.x before 1.25.4, and 1.26.x before 1.26.1. This vulnerability specifically manifests when MediaWiki is configured with relative URLs, creating a pathway for remote authenticated attackers to execute malicious web scripts or HTML code within the context of other users' browsers. The flaw operates through wikitext injection, where attackers can manipulate wiki links to trigger XSS payloads, as demonstrated by the specific example of a wikilink pointing to a page named "javascript:alert('XSS!')". This vulnerability falls under CWE-79, which categorizes cross-site scripting as a weakness where untrusted data is improperly embedded into web pages, and aligns with ATT&CK technique T1203, which covers exploitation of web applications through injection attacks.
The technical implementation of this vulnerability stems from improper handling of relative URLs within MediaWiki's link processing mechanisms. When the platform processes wikitext containing links to pages that match specific patterns such as "javascript:" protocols, the application fails to adequately sanitize or validate these inputs before rendering them in the browser context. This occurs because the relative URL configuration does not properly distinguish between legitimate web content and potentially malicious script execution attempts. The vulnerability specifically exploits the trust relationship between the MediaWiki application and its users, where authenticated users can create or modify content that will be executed by other users who view the affected pages. This creates a persistent threat vector that can be leveraged for session hijacking, credential theft, or redirection to malicious sites.
The operational impact of CVE-2015-8622 extends beyond simple script execution, as it can be weaponized to create sophisticated attack chains within wiki environments. An attacker with authenticated access can craft malicious wiki pages that, when viewed by other users, execute arbitrary JavaScript code in their browser context. This capability enables various attack vectors including cookie theft through document.cookie manipulation, redirection to phishing sites, or even more complex attacks such as credential harvesting through form submission interception. The vulnerability particularly affects collaborative wiki environments where multiple users contribute content, as the attack can be initiated by any authenticated user with editing privileges, making it a significant concern for organizations relying on MediaWiki for documentation, knowledge management, or collaborative platforms. The widespread adoption of MediaWiki across educational institutions, government agencies, and enterprise organizations amplifies the potential impact of this vulnerability.
Mitigation strategies for CVE-2015-8622 primarily focus on immediate version upgrades to patched releases, specifically implementing MediaWiki versions 1.23.12, 1.24.5, 1.25.4, or 1.26.1 respectively. Organizations should also implement comprehensive input validation and sanitization measures, particularly for wikitext processing, to prevent the execution of dangerous URL protocols. Security configurations should include strict content security policy enforcement, which can prevent execution of inline scripts and restrict the sources from which scripts can be loaded. Additionally, implementing web application firewalls with XSS detection capabilities can provide additional layers of protection. Network administrators should consider implementing privileged user access controls and monitoring for unusual content creation patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper URL handling in web applications and underscores the necessity of thorough input validation, particularly when dealing with user-generated content that can be rendered in browser contexts, aligning with ATT&CK technique T1190 which addresses the exploitation of web applications through input validation flaws.