CVE-2022-29233 in BigBlueButton
Summary
by MITRE • 06/02/2022
BigBlueButton is an open source web conferencing system. In BigBlueButton starting with 2.2 but before 2.3.18 and 2.4-rc-1, an attacker can circumvent access controls to gain access to all breakout rooms of the meeting they are in. The permission checks rely on knowledge of internal ids rather than on verification of the role of the user. Versions 2.3.18 and 2.4-rc-1 contain a patch for this issue. There are currently no known workarounds.
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Analysis
by VulDB Data Team • 06/04/2022
The vulnerability identified as CVE-2022-29233 affects BigBlueButton, an open source web conferencing system widely used for virtual meetings and online education platforms. This security flaw represents a critical access control bypass issue that undermines the fundamental security model of the platform's breakout room functionality. The vulnerability exists in versions starting with 2.2 but before 2.3.18 and 2.4-rc-1, creating a window of exposure where unauthorized users can exploit the system's permission mechanisms to gain access to all breakout rooms within a meeting. The flaw specifically targets the authentication and authorization checks that govern user access to breakout room features, fundamentally compromising the integrity of the system's access control architecture.
The technical implementation of this vulnerability stems from a design flaw in how BigBlueButton handles user permissions for breakout rooms. Rather than properly verifying user roles and privileges through robust authentication mechanisms, the system relies on internal identifiers that can be easily guessed or enumerated by attackers. This approach violates fundamental security principles and creates a path for privilege escalation where malicious actors can bypass normal access controls by simply knowing or discovering internal ID values. The vulnerability directly maps to CWE-284, which describes improper access control issues where systems fail to properly enforce access restrictions. This weakness allows attackers to perform unauthorized actions that should be restricted based on user roles, effectively undermining the role-based access control (RBAC) model that should govern the system's behavior.
The operational impact of this vulnerability is significant for organizations relying on BigBlueButton for sensitive meetings, educational sessions, or corporate training. An attacker who gains access to a meeting can potentially access all breakout rooms regardless of their actual role or permissions, which could lead to unauthorized access to private discussions, sensitive information sharing, or disruption of planned meeting activities. This vulnerability particularly affects environments where breakout rooms are used for confidential discussions, such as legal consultations, medical consultations, or strategic business planning sessions. The attack vector is relatively straightforward as it requires only knowledge of internal ID structures, making it accessible to attackers with basic technical skills. The vulnerability also aligns with ATT&CK technique T1078 which covers valid accounts usage, as attackers can leverage legitimate meeting access to escalate privileges within the system.
The remediation for this vulnerability requires immediate upgrade to patched versions 2.3.18 or 2.4-rc-1 of BigBlueButton, as no workarounds are currently available. Organizations should implement comprehensive monitoring of meeting activities and access logs to detect potential exploitation attempts. Security teams should also review and audit existing breakout room configurations to ensure proper access controls are in place. The patched versions address the core issue by implementing proper role verification mechanisms instead of relying on internal identifier checks, thereby restoring the intended access control model. Organizations using older versions should prioritize patching to prevent potential exploitation, as the vulnerability creates a persistent risk for any deployment that has not been updated. This vulnerability highlights the importance of proper access control implementation and the dangers of relying on obscurity as a security mechanism rather than implementing robust authentication and authorization checks.