auditing-message-broker-topic-authorizationlisted

# Auditing message-broker topic authorization: when a wildcard subscribes to everyone A message broker is a shared channel that many producers and consumers, often many tenants, talk through, and topic authorization is what keeps one client's messages from reaching another's. That boundary is thinner than it looks. Authenticating to the broker is not the same as being authorized per topic: a broker that checks the connection but not the topic lets any authenticated client read or write any topic. Wildcards make it worse, a subscription with a wildcard can match another tenant's topics and receive their messages, and a broad publish permission can inject into a control or command topic that consumers act on. And on a shared broker, topic naming is frequently the only thing separating tenants, which is a convention, not an enforced boundary. The audit asks, for each client, exactly which topics it can publish to and subscribe to, and whether that matches its role. You audit this by enumerating effective topic permissions and testing cross-tenant reach. ## When to use - A broker (MQTT, Kafka, AMQP, or similar) carries messages across producer, consumer, or tenant boundaries. - Clients authenticate to the broker but topic-level publish and subscribe authorization may be missing. - Wildcard subscriptions or broad publish grants may cross topics or tenants on a shared broker. ## Scope check Test broker authorization only on brokers you own or are authorized to assess, on non-p