Cyber-Security Evaluation for a Hypothetical Nuclear Power Plant using the Attack Tree Method

Abstract

The widespread introduction of digital network systems in nuclear power plants has increased such infrastructures vulnerability to cyber-attacks. The attack tree approach to evaluate and analyze cyber-attacks quantitatively, in a nuclear power plants' network system is presented in this work. Information on a hypothetical nuclear power plants' network system was used to build attack trees that show different attack paths that external adversaries can use to compromise the network system. To assert the ease or difficulty of compromising each attack tree, numerical values are assigned to the leaf nodes of each attack tree. The return on attack for each intermediate node and the root node are then calculated. This calculation is done by randomly varying the vulnerability values of the leaf nodes within the designated range. On observing high return of attack values with the two attack trees developed, counter measures were then implemented. Modified network systems were constructed and the return on attack recalculated. The return on attack (ROA) values for the nodes were observed to decrease, after implementing the counter measures on the network security systems.

Keywords: Attack tree, cyber-attacks, cyber-security, return on attack, vulnerability assessment