CVE-2019-12467 in MediaWiki
Summary
by MITRE
MediaWiki through 1.32.1 has Incorrect Access Control (issue 1 of 3). A spammer can use Special:ChangeEmail to send out spam with no rate limiting or ability to block them. Fixed in 1.32.2, 1.31.2, 1.30.2 and 1.27.6.
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Analysis
by VulDB Data Team • 07/07/2024
The vulnerability identified as CVE-2019-12467 represents a critical access control flaw within MediaWiki versions up to 1.32.1 that enables unauthorized spam distribution through the Special:ChangeEmail functionality. This issue falls under the broader category of improper access control mechanisms as defined by CWE-284, where the system fails to properly enforce authorization checks for specific operations. The vulnerability specifically affects the email change feature that lacks proper rate limiting and user blocking capabilities, creating an exploitable pathway for malicious actors to conduct spam campaigns.
The technical implementation of this flaw allows spammers to leverage the Special:ChangeEmail interface without adequate restrictions on usage frequency or user identification mechanisms. This interface typically serves legitimate purposes for users to update their email addresses, but the absence of rate limiting enables automated scripts to rapidly submit multiple email change requests. The lack of blocking mechanisms means that even if individual spam attempts are detected, there is no systematic approach to prevent repeat offenses from the same source. This vulnerability aligns with ATT&CK technique T1566 which involves phishing and social engineering through spam campaigns, and specifically targets the credential access and privilege escalation phases of the attack lifecycle.
The operational impact of this vulnerability extends beyond simple spam distribution to potentially compromise user trust and system integrity within MediaWiki deployments. Organizations running affected versions face significant risks including email server overload, reputation damage, and potential exploitation for more sophisticated attacks such as credential harvesting or account takeover attempts. The vulnerability affects all versions of MediaWiki from 1.27.0 through 1.32.1, indicating a prolonged period of exposure across multiple release lines. This widespread impact suggests that numerous websites and platforms relying on MediaWiki for content management were potentially vulnerable to abuse, with the attack surface expanding to include any system administrator who has not yet upgraded to the patched versions.
The remediation for this vulnerability requires immediate deployment of the patched versions 1.32.2, 1.31.2, 1.30.2, and 1.27.6 which implement proper rate limiting and blocking mechanisms for the Special:ChangeEmail functionality. Security administrators should also consider implementing additional monitoring for unusual email change activity patterns and review existing access controls to ensure that similar vulnerabilities do not exist in other interfaces. The fix addresses the root cause by introducing proper rate limiting that prevents excessive requests from single users or IP addresses, combined with enhanced user blocking capabilities that can prevent repeat spam attempts. Organizations should conduct thorough testing of the updated systems to ensure that legitimate user functionality remains intact while the malicious spamming capabilities are effectively mitigated. This vulnerability demonstrates the critical importance of implementing proper access controls and rate limiting mechanisms for all user-facing interfaces, particularly those that handle sensitive information such as email addresses and user credentials.