Apache ZooKeeper: Insufficient Permission Check in AdminServer Snapshot/Restore Commands

Improper permission checks in the AdminServer allow an authenticated client with insufficient privileges to invoke the snapshot and restore commands. The intended requirement is authentication and authorization on the root path (/) with ALL permission for these operations; however, affected versions permit invocation without that level of authorization. The primary risk is disclosure of cluster state via snapshots to a lesser-privileged client.

• Affected: org.apache.zookeeper:zookeeper 3.9.0 through 3.9.3.
• Fixed: 3.9.4 (ZOOKEEPER-4964 “check permissions individually during admin server auth”).
• Mitigations:
• Disable both commands (admin.snapshot.enabled, admin.restore.enabled).
• Disable AdminServer (admin.enableServer).
• Ensure the root ACL is not open; note that ZooKeeper ACLs are not recursive.
• Upgrade to 3.9.4.