CVE-2014-5241 in MediaWiki
Summary
by MITRE
The JSONP endpoint in includes/api/ApiFormatJson.php in MediaWiki before 1.19.18, 1.20.x through 1.22.x before 1.22.9, and 1.23.x before 1.23.2 accepts certain long callback values and does not restrict the initial bytes of a JSONP response, which allows remote attackers to conduct cross-site request forgery (CSRF) attacks, and obtain sensitive information, via a crafted OBJECT element with SWF content consistent with a restricted character set.
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Analysis
by VulDB Data Team • 02/10/2022
The vulnerability identified as CVE-2014-5241 affects MediaWiki versions prior to specific patch releases, specifically targeting the JSONP endpoint implementation in the ApiFormatJson.php file. This flaw exists within the includes/api/ directory of the MediaWiki software ecosystem, representing a critical security oversight that undermines the platform's ability to properly validate and sanitize user input. The vulnerability stems from insufficient validation of callback parameter values in the JSONP functionality, which is commonly used for cross-domain data retrieval in web applications.
The technical flaw manifests through the improper handling of callback parameters in JSONP requests where the system accepts excessively long callback values without adequately restricting the initial bytes of the JSONP response. This allows malicious actors to manipulate the callback parameter to include crafted OBJECT elements containing SWF content that aligns with restricted character sets. The vulnerability specifically leverages the lack of proper input sanitization and validation mechanisms that should normally prevent the inclusion of potentially harmful content within JSONP responses. The absence of proper restrictions on the initial bytes of the response creates an opening for attackers to inject malicious code that can bypass normal security controls.
The operational impact of this vulnerability extends beyond simple cross-site request forgery attacks to include the potential for sensitive information disclosure. Attackers can exploit this weakness to conduct CSRF attacks against authenticated users, potentially accessing privileged data or performing unauthorized actions within the MediaWiki environment. The vulnerability particularly affects systems where MediaWiki serves as a content management platform for organizations with sensitive information, as it could allow unauthorized access to wiki content, user data, or administrative functions. The attack vector becomes particularly dangerous in environments where users may inadvertently interact with malicious content through embedded SWF objects that are processed by the vulnerable JSONP endpoint.
This vulnerability maps to CWE-346, which addresses the issue of "Origin Validation Error" in web applications, and aligns with ATT&CK technique T1213.002 for "Accessing/Extracting Data from Web Applications." The flaw represents a classic example of insufficient input validation combined with improper output encoding that allows attackers to manipulate the intended behavior of the JSONP functionality. Organizations using affected MediaWiki versions face significant risk of data breaches and unauthorized access, particularly in environments where the wiki serves as a repository for confidential information or serves as a platform for collaborative work involving sensitive data.
The recommended mitigation strategy involves upgrading to the patched versions of MediaWiki that address this specific vulnerability, with the affected versions being 1.19.18, 1.22.9, and 1.23.2 respectively. Additionally, administrators should implement proper input validation measures for callback parameters, including length restrictions and character set validation. The implementation of Content Security Policy headers and proper CORS configuration can provide additional defense-in-depth measures. Organizations should also conduct thorough security assessments of their MediaWiki installations to identify any other potential vulnerabilities in related components or extensions that might interact with the JSONP functionality. Regular security updates and patch management processes should be implemented to prevent similar vulnerabilities from occurring in future releases.