A security system with methodology for interprocess communication control is described. In one embodiment, a method for controlling interprocess communication is provided that includes steps of: defining rules indicating which system services a given application can invoke; trapping an attempt by a particular application to invoke a particular system service; identifying the particular application that is attempting to invoke the particular system service; and based on identity of the particular application and on the rules indicating which system services a given application can invoke, blocking the attempt when the rules indicate that the particular application cannot invoke the particular system service.