CVE-2024-6428 in Mattermost
Summary
by MITRE • 07/03/2024
Mattermost versions 9.8.0, 9.7.x <= 9.7.4, 9.6.x <= 9.6.2, 9.5.x <= 9.5.5 fail to prevent specifying a RemoteId when creating a new user which allows an attacker to specify both a remoteId and the user ID, resulting in creating a user with a user-defined user ID. This can cause some broken functionality in User Management such administrative actions against the user not working.
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Analysis
by VulDB Data Team • 07/06/2024
The vulnerability identified as CVE-2024-6428 affects Mattermost server versions 9.8.0, 9.7.x up to 9.7.4, 9.6.x up to 9.6.2, and 9.5.x up to 9.5.5, representing a critical authorization and user management flaw that undermines the integrity of the platform's user identification system. This issue stems from insufficient validation mechanisms within the user creation process that fails to properly enforce the distinction between local and remote user identifiers, creating a scenario where malicious actors can manipulate user attributes during account provisioning.
The technical flaw manifests when an attacker exploits the user creation API endpoint by providing both a remoteId parameter and a user ID parameter simultaneously during the user creation process. This dual specification bypasses the normal validation checks that should prevent such conflicts, allowing the system to accept a user-defined identifier rather than generating an automatically assigned one. The vulnerability resides in the server-side validation logic that should enforce strict separation between local user identifiers and remote authentication system identifiers, particularly within the mattermost server's user management service layer.
The operational impact of this vulnerability extends beyond simple user identification conflicts and can severely compromise administrative capabilities within the Mattermost environment. When users are created with predetermined user IDs, administrative actions such as user suspension, deletion, permission modifications, and audit tracking become unreliable or completely ineffective. This creates a persistent security risk where attackers can potentially maintain unauthorized access to user accounts while evading detection mechanisms, as the system's user management functions become inconsistent and unreliable. The vulnerability essentially allows for the creation of accounts that can bypass standard administrative controls and may lead to privilege escalation scenarios.
This vulnerability maps directly to CWE-284: Improper Access Control and CWE-306: Missing Authentication for Critical Function, as it represents a failure in access control mechanisms that should prevent unauthorized modification of user attributes. The issue also aligns with ATT&CK technique T1078.004: Valid Accounts, where adversaries may leverage legitimate user accounts to maintain persistent access. Organizations using affected Mattermost versions face significant risk of unauthorized user account manipulation and potential privilege escalation. The recommended mitigation involves upgrading to patched versions of Mattermost, implementing additional validation layers at the application level, and conducting thorough user account audits to identify any compromised accounts that may have been created using this vulnerability.