Assessing Cyber-Physical Security in Industrial Control Systems

TL;DR

This paper introduces a novel security metric for industrial control systems using AND/OR hypergraphs and MAX-SAT techniques to identify critical components with minimal attacker effort, demonstrated through a water network case study.

Contribution

It presents an extended security metric based on AND/OR hypergraphs and MAX-SAT, enabling efficient identification of critical ICS components and security measures.

Findings

The method effectively identifies critical components with minimal attack effort.

Performance evaluation shows the approach is feasible for real-world ICS.

Case study demonstrates practical application in a water transport network.

Abstract

Over the last years, Industrial Control Systems (ICS) have become increasingly exposed to a wide range of cyber-physical threats. Efficient models and techniques able to capture their complex structure and identify critical cyber-physical components are therefore essential. AND/OR graphs have proven very useful in this context as they are able to semantically grasp intricate logical interdependencies among ICS components. However, identifying critical nodes in AND/OR graphs is an NP-complete problem. In addition, ICS settings normally involve various cyber and physical security measures that simultaneously protect multiple ICS components in overlapping manners, which makes this problem even harder. In this paper, we present an extended security metric based on AND/OR hypergraphs which efficiently identifies the set of critical ICS components and security measures that should be compromised, with minimum cost (effort) for an attacker, in order to disrupt the operation of vital ICS assets. Our approach relies on MAX-SAT techniques, which we have incorporated in META4ICS, a Java-based security metric analyser for ICS. We also provide a thorough performance evaluation that shows the feasibility of our method. Finally, we illustrate our methodology through a case study in which we analyse the security posture of a realistic Water Transport Network (WTN).