An attack control device according to an embodiment is provided with a storage unit and one or more hardware processors configured to function as a selection unit, a determination unit, and a calculation unit. The storage unit associates and stores a normal communication data model representing a model of communication data of a normal system, with each network segment. The selection unit specifies the network segment based on the communication prediction data predicted upon execution of the attack scenario and selects the normal communication data model associated with the network segment. The determination unit determines the similarity degree between the normal communication data represented by the normal communication data model, and the communication prediction data. The calculation unit calculates an effectiveness degree of the attack scenario to be higher as the similarity degree is higher.