CVE-2014-9476 in MediaWiki
Summary
by MITRE
MediaWiki 1.2x before 1.22.15, 1.23.x before 1.23.8, and 1.24.x before 1.24.1 allows remote attackers to bypass CORS restrictions in $wgCrossSiteAJAXdomains via a domain that has a partial match to an allowed origin, as demonstrated by "http://en.wikipedia.org.evilsite.example/."
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 04/11/2022
The vulnerability identified as CVE-2014-9476 represents a critical cross-origin resource sharing (CORS) restriction bypass in MediaWiki versions prior to specific patch releases. This flaw exists within the web application's implementation of cross-site AJAX domain validation mechanisms, where the system fails to properly validate domain matches against allowed origins. The vulnerability specifically affects MediaWiki 1.2x versions before 1.22.15, 1.23.x versions before 1.23.8, and 1.24.x versions before 1.24.1, creating a security gap that could be exploited by remote attackers to circumvent intended access controls.
The technical implementation flaw stems from improper domain validation logic that performs only partial string matching rather than comprehensive domain verification. When an attacker crafts a malicious URL such as "http://en.wikipedia.org.evilsite.example/", the system incorrectly accepts this as a valid cross-origin request because it contains the legitimate domain "en.wikipedia.org" within the constructed malicious domain. This partial matching approach violates the fundamental security principle of exact domain validation and allows attackers to bypass the intended CORS restrictions that should prevent unauthorized cross-site requests. The vulnerability operates at the application layer and specifically targets the configuration parameter $wgCrossSiteAJAXdomains which controls which domains can make cross-site AJAX requests to the MediaWiki instance.
The operational impact of this vulnerability is significant as it enables remote attackers to perform cross-site request forgery attacks and potentially access sensitive data through unauthorized AJAX requests. Attackers can exploit this flaw to make authenticated requests to the MediaWiki instance from malicious domains, potentially leading to data exfiltration, account takeovers, or privilege escalation within the MediaWiki environment. The vulnerability essentially undermines the security model that CORS is designed to enforce, allowing malicious actors to bypass the same-origin policy enforcement mechanisms that protect against unauthorized cross-site interactions. This issue particularly affects collaborative platforms where MediaWiki instances host sensitive information and user data, making it a serious concern for organizations relying on these systems for content management.
The vulnerability aligns with CWE-346, which addresses "Improper Verification of Source of a Communication Channel," and relates to the ATT&CK technique T1071.001 for application layer protocol usage. Organizations should immediately apply the security patches released by MediaWiki for the affected versions, specifically upgrading to MediaWiki 1.22.15, 1.23.8, or 1.24.1 respectively. Additionally, administrators should review and tighten their CORS configuration settings to ensure that only exact domain matches are permitted rather than allowing partial matches. The mitigation strategy should include implementing proper domain validation mechanisms that verify complete domain names against allowed origins and removing any legacy configurations that permit partial domain matching. Network-level monitoring should also be enhanced to detect suspicious cross-site requests that attempt to exploit this vulnerability through crafted domain names.