Can you explain this vulnerability to me?

This vulnerability exists in Portainer Community Edition versions from 2.33.0 to before 2.33.8, 2.39.2, and 2.41.0. Portainer has a security setting called "Disable bind mounts for non-administrators" which is intended to prevent regular users from binding host paths into containers they create. However, the enforcement of this setting only checked the legacy HostConfig.Binds array and did not inspect the HostConfig.Mounts array. As a result, any authenticated user with container creation rights could bypass this restriction by submitting a bind mount entry under HostConfig.Mounts, allowing them to mount any host path into their container.

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How can this vulnerability impact me? :

This vulnerability can allow an authenticated user with container creation permissions to mount arbitrary host paths into their containers, bypassing security restrictions. This could lead to unauthorized access to sensitive files or directories on the host system, potentially exposing confidential data or enabling further attacks within the environment.

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What immediate steps should I take to mitigate this vulnerability?

To mitigate this vulnerability, you should upgrade Portainer Community Edition to one of the fixed versions: 2.33.8, 2.39.2, or 2.41.0.

This vulnerability arises because the security setting that disables bind mounts for non-administrators does not properly check the HostConfig.Mounts array, allowing authenticated users with container creation rights to mount any host path.

Upgrading to a fixed version ensures that the check properly inspects both HostConfig.Binds and HostConfig.Mounts, preventing unauthorized bind mounts.

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How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:

This vulnerability allows authenticated users with container creation rights to bypass restrictions and mount arbitrary host paths into containers, potentially exposing sensitive host filesystem data.

Such unauthorized access to host files could lead to exposure or compromise of sensitive data, which may impact compliance with data protection regulations like GDPR and HIPAA that require strict controls over access to personal and protected health information.

Therefore, if exploited, this vulnerability could undermine the security controls necessary to maintain compliance with these standards by enabling unauthorized data access and persistence on the host.

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How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability involves a bypass of the bind-mount restriction in Portainer by submitting bind mounts via the HostConfig.Mounts field instead of the legacy HostConfig.Binds field. Detection involves monitoring container creation requests to the Docker API mediated by Portainer, specifically looking for bind-typed entries under HostConfig.Mounts from non-administrator users.

Since the vulnerability requires an authenticated user with container creation rights, detection can focus on auditing container creation API calls and inspecting the payload for suspicious bind mounts.

Suggested commands or approaches include:

• Use Docker API or CLI to inspect recently created containers for bind mounts that may have been created via HostConfig.Mounts. For example, run `docker inspect <container_id>` and check the Mounts section for unexpected host path bindings.
• Audit Portainer logs or API request logs to identify container creation requests from non-administrator users that include bind mounts under HostConfig.Mounts.
• If you have access to the Docker daemon logs or audit logs, search for container creation events with bind mounts that bypass the expected restrictions.
• Temporarily revoke container creation rights for non-administrator users to prevent exploitation until the system is patched.

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