A security unit for an industrial control system comprises an interface adapted to communicate with a plurality of components of an industrial control system via a data network, a security assignor adapted to access a first component among the plurality of components via the interface, and further adapted to assign a first security level pertaining to the first component to the first component. The security assignor is further adapted to access a second component among the plurality of components via the interface, and to assign a second security level pertaining to the second component to the second component. The security assignor is adapted to assign the first security level and the second security level to the first component and the second component, respectively, in accordance with a system security level pertaining to the industrial control system.