A method for detecting an attack, in particular a cyber-attack, on a control device of a vehicle, with the step of: checking communication data that is transmitted via at least one communication channel of the vehicle that is connected to the control device, wherein the checking of the communication data that is transmitted via the at least one communication channel of the vehicle that is connected to the control device includes the examination of whether the communication data transmitted via the at least one communication channel of the vehicle fulfils data requirements that are defined by one or a plurality of changeable rules.