Method and intrusion detection unit for verifying message behavior

An intrusion detection unit in a component of an automation system, wherein the components of the automation system communicate with one another and with a control unit via a communication network, and wherein the intrusion detection unit is designed to verify a message behavior of the control unit locally, the intrusion detection unit comprising:

• a receiving unit adapted to receive at least one message via the communication network for the purpose of controlling the component;
• an analysis interface to an analysis unit adapted to analyze the at least one received message according to a characteristic message description stored in a component memory;
• and
• a verification interface to a verification unit which is adapted to verify the message behavior as permissible if the analysis message corresponds to the characteristic message description.