CVE-2019-19709 in MediaWiki
Summary
by MITRE
MediaWiki through 1.33.1 allows attackers to bypass the Title_blacklist protection mechanism by starting with an arbitrary title, establishing a non-resolvable redirect for the associated page, and using redirect=1 in the action API when editing that page.
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Analysis
by VulDB Data Team • 03/10/2024
The vulnerability identified as CVE-2019-19709 represents a significant bypass of MediaWiki's title blacklist protection mechanism, which is designed to prevent the creation of pages with potentially malicious or inappropriate titles. This flaw exists within MediaWiki versions through 1.33.1 and allows attackers to circumvent content restrictions by exploiting the interaction between page titles, redirects, and the action API. The vulnerability specifically targets the system's ability to enforce title blacklists during page creation and editing operations, creating a pathway for malicious actors to inject content that would otherwise be blocked by administrative policies.
The technical implementation of this vulnerability relies on a sophisticated manipulation of MediaWiki's redirect handling system combined with the action API's editing capabilities. Attackers can begin by creating a page with an arbitrary title that would normally be blocked by the blacklist, then establish a non-resolvable redirect for that page. When editing the page subsequently, they utilize the redirect=1 parameter within the action API to modify the page content. This technique effectively bypasses the title validation checks because the system processes the redirect mechanism separately from the initial title blacklist enforcement, allowing malicious content to be added through the redirect chain rather than directly through the blocked title.
The operational impact of this vulnerability extends beyond simple content injection, as it undermines the fundamental security controls that administrators rely upon to maintain content integrity and prevent the creation of harmful or inappropriate material. Organizations using MediaWiki for collaborative platforms, documentation systems, or knowledge bases face significant risks when this vulnerability exists, as attackers can potentially create pages with malicious links, spam content, or violate organizational policies without detection. The vulnerability particularly affects systems where title blacklists are configured to prevent specific keywords, patterns, or known malicious titles, making it a critical concern for any environment that depends on these protection mechanisms.
This vulnerability aligns with CWE-284 Access Control Issues, specifically demonstrating how improper access control enforcement can be exploited through indirect manipulation of system components. The flaw also relates to ATT&CK technique T1078 Valid Accounts, as it allows attackers to bypass security controls without requiring elevated privileges or special authentication mechanisms. Organizations should implement immediate mitigations including upgrading to MediaWiki version 1.33.2 or later, where this vulnerability has been patched, and reviewing existing title blacklist configurations to ensure they are properly enforced throughout the system's redirect handling processes. Additionally, administrators should consider implementing additional monitoring and logging controls around page creation and editing activities, particularly those involving redirect parameters, to detect potential exploitation attempts and maintain visibility into content modification activities within their MediaWiki installations.