CVE-2016-6335 in MediaWiki
Summary
by MITRE
MediaWiki before 1.23.15, 1.26.x before 1.26.4, and 1.27.x before 1.27.1 does not generate head items in the context of a given title, which allows remote attackers to obtain sensitive information via a parse action to api.php.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 09/18/2020
This vulnerability exists in MediaWiki versions prior to 1.23.15, 1.26.4, and 1.27.1 where the application fails to properly generate head items when processing parse actions through the api.php endpoint. The flaw stems from insufficient input validation and output sanitization mechanisms that allow malicious actors to manipulate the parsing process and extract sensitive information from the system. When users submit parse requests to the api.php interface, the system does not adequately control the generation of head elements associated with specific titles, creating an information disclosure channel that can be exploited by remote attackers.
The technical implementation of this vulnerability involves the improper handling of title contexts within the MediaWiki parsing framework. Attackers can craft malicious API requests that trigger the parsing of specific titles while bypassing normal security controls that would typically prevent sensitive data exposure. This weakness falls under the category of information disclosure vulnerabilities and aligns with CWE-200, which addresses improper information exposure. The vulnerability is particularly concerning because it leverages legitimate API functionality to achieve unauthorized information access, making detection more challenging for security monitoring systems.
The operational impact of CVE-2016-6335 extends beyond simple information leakage, as the exposed data could include system configuration details, user metadata, or other sensitive information that could aid in further exploitation attempts. Remote attackers can systematically query the api.php endpoint to gather intelligence about the MediaWiki installation, potentially identifying version-specific vulnerabilities, configuration weaknesses, or user account information. This information can be used to plan more sophisticated attacks or to tailor subsequent exploitation techniques to the specific target environment. The vulnerability demonstrates a failure in the principle of least privilege, where the system does not properly restrict access to sensitive information during legitimate parsing operations.
Organizations using affected MediaWiki versions should prioritize immediate patching to address this vulnerability. The recommended mitigation strategy involves upgrading to the patched versions 1.23.15, 1.26.4, or 1.27.1, which contain proper head item generation controls and enhanced input validation. Additional protective measures include implementing API rate limiting to prevent automated exploitation attempts, configuring proper access controls for the api.php endpoint, and monitoring for unusual parsing activity patterns. From an ATT&CK framework perspective, this vulnerability maps to T1083 (File and Directory Discovery) and T1566 (Phishing with Malicious Attachments) as attackers could use the exposed information to craft more targeted attacks. Network segmentation and firewall rules should be implemented to restrict access to the api.php endpoint to trusted IP addresses only, while regular security audits should verify that no sensitive information is being inadvertently exposed through parsing operations.