The Critical Node Game. (arXiv:2303.05961v1 [math.OC])

Cloud networks are the backbone of the modern distributed internet
infrastructure as they provision most of the on-demand resources organizations
and individuals use daily. However, any abrupt cyber-attack could disrupt the
provisioning of some of the cloud resources fulfilling the needs of customers,
industries, and governments. In this work, we introduce a game-theoretic model
that assesses the cyber-security risk of cloud networks and informs security
experts on the optimal security strategies. Our approach combines game theory,
combinatorial optimization, and cyber-security and aims at minimizing the
unexpected network disruptions caused by malicious cyber-attacks under
uncertainty. Methodologically, our approach consists of a simultaneous and
non-cooperative attacker-defender game where each player solves a combinatorial
optimization problem parametrized in the variables of the other player.
Practically, our approach enables security experts to (i.) assess the security
posture of the cloud network, and (ii.) dynamically adapt the level of
cyber-protection deployed on the network. We provide a detailed analysis of a
real-world cloud network and demonstrate the efficacy of our approach through
extensive computational tests.