1. A method comprising the steps of: identifying a plurality of defensive security actions to be taken to address a persistent security threat; and determining a schedule for performance of the defensive security actions based at least in part on a selected distribution derived from a game-theoretic model; wherein a system comprising information technology infrastructure subject to the persistent security threat is configured to perform the defensive security actions in accordance with the schedule in order to deter the persistent security threat; wherein the selected distribution comprises a modified exponential distribution given by a combination of an exponential distribution and at least one other distribution; and wherein the steps are performed by a processing device comprising a processor coupled to a memory.