A method for averting a manipulation on a CAN bus using a first node connected to the bus by a CAN controller includes a secured transmit module of the first node monitoring the bus; the transmit module recognizing transmission processes of the CAN controller in a normal operation of the first node; the transmit module recognizing a message transmitted impermissibly on the bus in a manner deviating from the normal operation; and, in the event the transmit module recognizes the message, the transmit module initiating countermeasures provided against the manipulation.