CVE-2015-2786 in MyBB
Summary
by MITRE
Unspecified vulnerability in MyBB (aka MyBulletinBoard) before 1.8.4 has unknown attack vectors related to "Group join request notifications sent to wrong group leaders."
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Analysis
by VulDB Data Team • 04/15/2018
The vulnerability identified as CVE-2015-2786 affects MyBB versions prior to 1.8.4 and relates to improper handling of group join request notifications within the bulletin board system. This issue falls under the category of access control and privilege management flaws, where the system fails to properly route notification messages to the correct administrative personnel responsible for group membership decisions. The unspecified nature of the attack vectors suggests that multiple pathways could potentially exploit this weakness, making the vulnerability particularly concerning for security assessments.
The technical flaw manifests in the group management subsystem where notification mechanisms do not properly validate or authenticate the intended recipients for group membership requests. This creates a scenario where users attempting to join specific groups may receive notifications intended for different group administrators, potentially exposing sensitive group membership decisions to unauthorized personnel. The vulnerability represents a breakdown in the principle of least privilege and proper access control enforcement, allowing for potential information disclosure and unauthorized influence over group membership processes. This type of flaw aligns with CWE-284 access control weaknesses and could enable privilege escalation or information leakage attacks.
The operational impact of this vulnerability extends beyond simple notification misrouting to potentially compromise the integrity of group-based access controls within the MyBB system. When group leaders receive notifications meant for other administrators, it creates confusion in the membership approval process and could allow malicious actors to manipulate group access permissions. Attackers might exploit this to gain unauthorized access to restricted group content or to interfere with legitimate group management activities. The vulnerability could enable persistent threats to maintain access to sensitive areas of the bulletin board system while remaining undetected through normal administrative monitoring.
Organizations using MyBB versions prior to 1.8.4 should prioritize immediate remediation through patching to address this vulnerability. The recommended mitigation involves upgrading to MyBB 1.8.4 or later versions where this notification routing issue has been resolved. Security teams should also implement monitoring of group membership request patterns to detect any unusual notification routing behavior that might indicate exploitation attempts. Additionally, administrators should review and validate group leader assignments to ensure proper access control enforcement. This vulnerability demonstrates the importance of proper notification system design and access control validation, aligning with ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting through social engineering or system manipulation. Organizations should also consider implementing network segmentation and access controls to limit potential lateral movement if the system is compromised through this vulnerability.