The Pulsar Functions worker REST API provides two endpoints that return the catalog of Pulsar IO connectors installed on the functions worker: the worker connectors endpoint (/admin/v2/worker/connectors) and the deprecated functions connectors endpoint (/admin/v2/functions/connectors and /admin/v3/functions/connectors). When authorization is enabled, the worker connectors endpoint requires super-user access. The functions connectors endpoint, served both by the functions worker and by a broker running the functions worker, returns the same catalog without this check.
As a result, when authentication and authorization are enabled, any authenticated client can read the connector catalog through the functions connectors endpoint, regardless of the permissions granted to its role and without super-user access. Unauthenticated requests are rejected unless anonymous access is configured with an anonymous user role.
The catalog contains the connector type definitions installed in the functions workers connectors directory: the connector name, its description, and the source, sink and configuration class names. It does not contain configured source or sink instances, their configuration values or credentials, and an installed connector type does not indicate that a connector is configured or running. The impact is limited to disclosure of this metadata, which can include the names and descriptions of custom connectors installed by the operator. The issue does not allow modifying the catalog or managing connectors. Connector definitions that have a source or sink class are also returned by the built-in sources and sinks endpoints to authenticated clients.
In fixed versions, the functions connectors endpoint applies the same checks as the worker connectors endpoint, so that it requires super-user access when authorization is enabled. Clients that are not super-users can use the built-in sources and sinks endpoints to list the available connector types.
This issue affects Apache Pulsar versions from 2.4.1 before 4.0.14 and from 4.1.0 before 4.2.5.
- 4.0.x version users should upgrade to at least 4.0.14.
- 4.1.x and 4.2.x version users should upgrade to at least 4.2.5.
Users operating versions prior to those listed above should upgrade to the aforementioned patched versions or newer versions.
The currently supported Apache Pulsar release lines are 4.0.x and 5.0.x. The supported versions schedule is available at https://pulsar.apache.org/contribute/release-policy/.
Weakness
The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
Potential Mitigations
- Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries.
- Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page.
- One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.