Defense timing selection for MTD in periodic satellite computing systems: A Markov game approach

Abstract

Satellite computing systems (SCSs), with their enormous economic value, are suffering from increasing attacks. Moving Target Defense (MTD), which changes the attack surface to create an asymmetric situation between attacks and defenses, can be used to improve the safety of the SCS. Defense timing selection is crucial for enhancing the defense capability of MTD and reducing its cost. However, existing MTD defense timing selection strategies do not consider limited defense resources and periodic user traffic in the SCS, which leads to significant resource consumption and impacts a large volume of traffic, making them unsuitable for the SCS. We propose a Markov Game-based Defense Timing Selection (MGDTS) approach to protect the SCS. We divide the orbital cycle of the SCS into several time periods with different traffic rates. For each period, we formulate the attack-defense adversarial relationship as a Markov game with incomplete information. In the game, we use explicit costs to define the resource consumption of a defender. Further, we employ Markov decision processes to construct the defense timing decision equation and use real-time dynamic programming to solve the equation. Experimental results show that compared with the existing MTDs, our scheme can enhance security while reducing resource consumption and the influence on user traffic. This work is an extended version of the ICCS-2024 conference paper (Lin Zhang et al., 2024).