Abstract: An information device performs data processing by executing program codes loaded in a memory with a central control unit. The information device includes a detection unit which detects a timing when any one of the program codes is called, a return address acquisition unit which sequentially acquires return addresses of the program codes loaded in the memory at the timing detected by the detection unit, and a termination unit which searches for an illegal access based on destination addresses that are respectively pointed by the return addresses sequentially acquired by the return address acquisition unit at the timing detected by the detection unit and which terminates the data processing when the illegal access is detected.