CVE-2015-3419 in vBulletin
Summary
by MITRE
vBulletin 5.x through 5.1.6 allows remote authenticated users to bypass authorization checks and inject private messages into conversations via vectors related to an input validation failure.
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Analysis
by VulDB Data Team • 11/17/2019
The vulnerability identified as CVE-2015-3419 affects vBulletin versions 5.x through 5.1.6 and represents a critical authorization bypass flaw that enables remote authenticated users to manipulate private messaging functionality. This vulnerability stems from inadequate input validation mechanisms within the application's message handling system, specifically targeting the conversation management components. The flaw allows attackers who have legitimate user accounts to exploit weaknesses in the permission checking logic, thereby gaining unauthorized access to private messaging features that should be restricted to authorized participants only.
The technical implementation of this vulnerability involves a failure in the application's input sanitization and validation processes within the private messaging module. When users submit messages or participate in conversations, the system does not properly verify whether the authenticated user has legitimate access rights to the target conversation or recipient. This input validation failure creates a pathway for privilege escalation where authenticated users can inject messages into private conversations they should not have access to, effectively bypassing the intended authorization controls. The vulnerability manifests through manipulation of request parameters that govern conversation membership and message routing, allowing attackers to exploit the lack of proper access control checks during message processing.
The operational impact of CVE-2015-3419 extends beyond simple unauthorized message injection, creating potential for significant data exposure and communication disruption within vBulletin-based forums. Attackers can leverage this vulnerability to eavesdrop on private conversations between legitimate users, potentially accessing sensitive personal information, confidential communications, or business-related discussions. The authorization bypass capability undermines the fundamental security model of private messaging systems, where users expect their communications to remain confidential between intended participants. This vulnerability can also enable social engineering attacks where malicious users can manipulate conversation threads to spread misinformation or compromise user trust in the platform's security measures.
Security professionals should note this vulnerability aligns with CWE-285, which addresses improper authorization in software systems, and maps to ATT&CK technique T1078 for valid accounts and privilege escalation. The flaw demonstrates a classic example of insufficient access control validation, where the application assumes that authenticated users can only access resources they are legitimately authorized to use. Organizations using affected vBulletin versions should implement immediate mitigations including applying the vendor-provided security patches, reviewing access control configurations, and monitoring for unauthorized access patterns in private messaging activities. Additionally, network segmentation and monitoring of private message traffic can help detect potential exploitation attempts, while user account management policies should be reviewed to ensure proper access control enforcement and regular security audits of messaging system components.
The broader implications of this vulnerability highlight the critical importance of robust input validation and authorization checking in web applications, particularly within community platforms where user-generated content and private communications are core features. This flaw demonstrates how seemingly minor input validation gaps can create significant security risks when combined with authentication mechanisms, emphasizing the need for comprehensive security testing and regular vulnerability assessments of web application components that handle sensitive user data and communications.