CVE-2011-1766 in MediaWiki
Summary
by MITRE
includes/User.php in MediaWiki before 1.16.5, when wgBlockDisablesLogin is enabled, does not clear certain cached data after verification of an auth token fails, which allows remote attackers to bypass authentication by creating crafted wikiUserID and wikiUserName cookies, or by leveraging an unattended workstation.
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Analysis
by VulDB Data Team • 11/07/2021
The vulnerability identified as CVE-2011-1766 resides within the MediaWiki software ecosystem, specifically within the includes/User.php file of versions prior to 1.16.5. This flaw manifests when the wgBlockDisablesLogin configuration parameter is enabled, creating a persistent security weakness that can be exploited by remote attackers to circumvent authentication mechanisms. The vulnerability stems from inadequate handling of cached data following failed authentication token verification processes, leaving residual information that can be manipulated to gain unauthorized access to user accounts.
The technical implementation of this vulnerability involves the improper clearing of cached authentication data when an authorization token verification fails. When wgBlockDisablesLogin is enabled, MediaWiki should prevent users from logging in if they are blocked, but the flaw allows attackers to exploit a caching mechanism that retains stale authentication state information. This occurs because the system fails to properly invalidate cached user session data when authentication attempts fail, particularly when dealing with crafted wikiUserID and wikiUserName cookies that contain manipulated authentication tokens. The flaw creates a condition where previously verified but now invalid authentication state information remains accessible to the application.
The operational impact of CVE-2011-1766 extends beyond simple unauthorized access to account compromise, potentially enabling attackers to assume the identity of legitimate users within the MediaWiki environment. This vulnerability is particularly dangerous because it can be exploited through multiple vectors including cookie manipulation and unattended workstation exploitation, making it applicable to both network-based attacks and physical security breaches. The attack surface is broadened when considering that MediaWiki is widely deployed across various organizations, from small wikis to large enterprise systems, potentially affecting thousands of user accounts and sensitive information repositories. This vulnerability directly relates to CWE-200, which addresses information exposure, and CWE-306, concerning missing authentication checks.
Attackers can leverage this vulnerability through several methods, with the most straightforward approach involving the creation of crafted cookies that contain manipulated authentication tokens. The flaw allows exploitation even when users are not actively using the system, making unattended workstations particularly vulnerable to unauthorized access. According to ATT&CK framework, this vulnerability maps to T1110.003, which covers credential guessing through password spraying, and T1078.004, which addresses valid accounts with default passwords or weak authentication. The vulnerability represents a significant risk to organizations using MediaWiki for collaborative environments, document management systems, and knowledge repositories where unauthorized access could lead to information disclosure, data manipulation, or system compromise.
Mitigation strategies for CVE-2011-1766 primarily focus on immediate software updates to MediaWiki version 1.16.5 or later, which contains the necessary patches to properly clear cached authentication data upon failed verification attempts. Organizations should also review their wgBlockDisablesLogin configuration settings and implement additional monitoring for suspicious authentication patterns. Network administrators should consider implementing additional authentication layers such as two-factor authentication and session management controls to reduce the impact of credential compromise. The vulnerability highlights the importance of proper session management and cache invalidation practices, aligning with security best practices outlined in NIST SP 800-63B for authentication and session management. Organizations should also conduct regular security assessments of their wiki environments to identify similar vulnerabilities and ensure proper patch management processes are in place to prevent exploitation of known security flaws.