Risk Analysis of Coordinated Cyber Attacks on Power Grid

The supervisory control and data acquisition (SCADA) network provides adversaries with an opportunity to perform coordinated cyber attacks on power system equipment as it presents an increased attack surface. Coordinated attacks, when smartly structured, can not only have severe physical impacts, but can also potentially nullify the effect of system redundancy and other defense mechanisms. This chapter proposes a vulnerability assessment framework to quantify risk due to intelligent coordinated attacks, where risk is defined as the product of probability of successful cyber intrusion and resulting power system impact. The cyber network is modeled using Stochastic Petri Nets and the steady-state probability of successful intrusion into a substation is obtained using this. The model employs a SCADA network with firewalls and password protection schemes. The impact on the power system is estimated by load unserved after a successful attack. The New England 39-bus system is used as a test model to run Optimal Power Flow (OPF) simulations to determine load unserved. We conduct experiments creating coordinated attacks from our attack template on the test system and evaluate the risk for every case. Our attack cases include combinations of generation units and transmission lines that form coordinated attack pairs. Our integrated risk evaluation studies provide a methodology to assess risk from different cyber network configurations and substation capabilities. Our studies identify scenarios, where generation capacity, cyber vulnerability, and the topology of the grid together could be used by attackers to cause significant power system impact.