Apache Pulsar: Improper Authorization of Function, Source and Sink Package URLs Allows Cross-Tenant Package Download

When package management is enabled, Pulsar Functions, Sources and Sinks can be registered or updated from a package stored in the Pulsar Packages Management Service by supplying a package URL. The Pulsar Functions worker authorized these requests only against the namespace in which the component was being registered or updated. It did not check whether the requesting user was permitted to access packages in the namespace that the package URL refers to, and it retrieved the package from the broker using the worker's own credentials. The permission check of the Packages Management Service was therefore applied to the worker's identity instead of the requesting user's. Package URLs of transform functions supplied when registering or updating a sink were handled in the same way.

An authenticated user who is permitted to register or update functions, sources or sinks in any namespace of their own tenant could use this to obtain the contents of a package stored in a namespace of another tenant, without having the packages permission on that namespace. The impact is limited to disclosure of package contents, which may include application code, business logic or embedded credentials. The issue does not allow packages to be modified or deleted and does not affect availability.

This issue only affects deployments that have authentication and authorization enabled and in which package management has been enabled: the broker setting enablePackagesManagement and, in current releases, the functions worker setting functionsWorkerEnablePackageManagement. Both settings are disabled by default.

This issue affects Apache Pulsar versions from 2.8.0 before 4.0.14, from 4.1.0 through 4.1.3, and from 4.2.0 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/.