Bot Account Deactivation via API in Mattermost

Executive Summary

This vulnerability affects Mattermost versions 11.7.x up to 11.7.0 and 10.11.x up to 10.11.17. It occurs because the software fails to enforce bot-specific permission checks on the user active status endpoint.

Specifically, a User Manager who has user management write access but does not have Integrations access can deactivate bot accounts by using the PUT /api/v4/users/{id}/active API endpoint.

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Impact Analysis

The vulnerability allows a User Manager without Integrations access to deactivate bot accounts, which they should not normally be able to do.

This could lead to disruption of automated processes or integrations that rely on bot accounts, potentially impacting system functionality or workflows.

The CVSS score of 3.8 indicates a low to medium severity impact, with no confidentiality loss but some integrity and availability impact.

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Mitigation Strategies

To mitigate this vulnerability, you should update Mattermost to a version later than 11.7.0 or 10.11.17 where the issue is fixed.

Additionally, review and restrict User Manager permissions to ensure that users with user management write access do not have unintended abilities to deactivate bot accounts.

Stay informed about security updates by monitoring Mattermost's official security updates page.

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Detection Guidance

This vulnerability involves the ability of a User Manager with user management write access but no Integrations access to deactivate bot accounts via the PUT /api/v4/users/{id}/active API endpoint.

To detect exploitation attempts on your system or network, you can monitor API requests targeting the endpoint PUT /api/v4/users/{id}/active, especially those made by users with User Manager roles but lacking Integrations access.

Suggested commands include inspecting web server or application logs for suspicious PUT requests to the user active status endpoint. For example, using grep on log files:

• grep 'PUT /api/v4/users/' /path/to/mattermost/logs/* | grep '/active'

Additionally, you can audit user roles and permissions within Mattermost to identify User Managers who might have the ability to perform such actions.

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