CVE-2016-9412 in MyBB
Summary
by MITRE
MyBB (aka MyBulletinBoard) before 1.8.7 and MyBB Merge System before 1.8.7 allow attackers to have unspecified impact via vectors related to low adminsid and sid entropy.
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Analysis
by VulDB Data Team • 08/08/2020
The vulnerability identified as CVE-2016-9412 affects MyBB forums and MyBB Merge System versions prior to 1.8.7, presenting a significant security risk through insufficient entropy in session identifiers. This weakness resides in the administrative session management system where the low entropy of adminsid and sid parameters creates predictable session tokens that attackers can exploit to gain unauthorized administrative access. The vulnerability stems from poor random number generation practices in the session identifier creation process, which violates fundamental security principles for session management as outlined in CWE-330. The impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with complete administrative control over affected systems, potentially enabling data exfiltration, user manipulation, and complete system compromise.
The technical flaw manifests through weak cryptographic randomness in session token generation, specifically affecting the adminsid and sid parameters used for administrative sessions. When session identifiers lack sufficient entropy, they become susceptible to prediction attacks where malicious actors can guess valid session tokens through brute force or statistical analysis. This vulnerability directly relates to CWE-330 which addresses insufficient entropy in random number generators, and represents a critical weakness in the authentication and session management framework. The low entropy values make it feasible for attackers to perform session hijacking attacks without requiring additional exploitation techniques, as the session tokens can be reasonably predicted or generated within a reasonable timeframe.
The operational impact of CVE-2016-9412 is severe and multifaceted, as it allows attackers to assume administrative privileges without requiring legitimate credentials or complex attack vectors. Once an attacker successfully predicts or obtains a valid adminsid or sid token, they gain complete control over the forum's administrative functions, including user management, content modification, plugin installation, and configuration changes. This vulnerability particularly affects online communities and forums that rely on MyBB for their platform infrastructure, potentially leading to widespread data compromise, user impersonation, and reputational damage. The attack surface is further expanded due to the predictable nature of the session identifiers, making this vulnerability exploitable in automated attack scenarios.
Mitigation strategies for CVE-2016-9412 primarily involve immediate upgrading to MyBB version 1.8.7 or later, which implements proper entropy generation for session identifiers. Organizations should also conduct thorough security assessments of their MyBB installations to verify that all session management components are properly configured with sufficient randomness. Network administrators should implement monitoring solutions to detect suspicious session activity and unusual login patterns that might indicate session hijacking attempts. Additional protective measures include implementing proper session timeout mechanisms, using secure session storage, and ensuring that all administrative access occurs through secure channels. The vulnerability also highlights the importance of following ATT&CK framework principles for session management and authentication, particularly in preventing credential exposure and unauthorized access through weak session identifiers. Organizations should also consider implementing multi-factor authentication for administrative accounts as an additional security layer to protect against session-based attacks.