Towards Optimal Cyber Defense Remediation in Energy Delivery Systems

Prioritized cyber defense remediation plan is critical for effective risk management in Energy Delivery System (EDS). Due to the complexity of EDS in terms of heterogeneous nature blending Information Technology (IT) and Operation Technology (OT) and Industrial Control System (ICS), scale and critical processes tasks, prioritized remediations should be applied gradually to protect critical assets. In this work, we propose a methodology for prioritized cyber risk remediation plan by detecting and evaluating paths to critical nodes in EDS. We propose critical nodes characteristics evaluation based on nodes' architectural positions, measure of centrality based on nodes' connectivity and frequency of network traffic, as well as the controlled amount of electrical power. The paper also examines the relationship between cost models of budget allocation for removal of vulnerabilities on critical nodes and its impact on gradual readiness. The proposed cost models were empirically validated in an actual network ICS test-bed computing nodes criticality. Two cost models were examined, and although varied, we concluded the lack of correlation between types of cost models to most damageable attack path and critical nodes readiness.