Biblio

Resilience and security of infrastructures depend not only on their constituent systems but also on interdependencies among them. This paper studies how these interdependencies in infrastructures affect the defense effort needed to counter external attacks, by formulating a simultaneous game between a service provider (i.e., defender) and an attacker. Effects of interdependencies in three basic topological structures, namely, bus, star and ring, are considered and compared in terms of the game-theoretic defense strategy. Results show that in a star topology, the attacker's and defender's pure strategies at Nash Equilibrium (NE) are sensitive to interdependency levels whereas in a bus structure, the interdependencies show little impact on both defender's and attacker's pure strategies. The sensitivity estimates of defense and attack strategies at NE with respect to target valuation and unit cost are also presented. The results provide insights into infrastructure design and resource allocation for reinforcement of constituent systems.

We address the need for security requirements to take into account risks arising from complex supply chains underpinning cyber-physical infrastructures such as industrial control systems (ICS). We present SEISMiC (SEcurity Industrial control SysteM supply Chains), a framework that takes into account the whole spectrum of security risks - from technical aspects through to human and organizational issues - across an ICS supply chain. We demonstrate the effectiveness of SEISMiC through a supply chain risk assessment of Natanz, Iran's nuclear facility that was the subject of the Stuxnet attack.