Defending the Homeland Against Critical Infrastructure Attacks: Exploring a Hypothetical Campaign of Cascading Impacts

In this report, we discuss threats to critical infrastructure (CI) and put forward a hypothetical case study to examine several phases of an adversarial attack on the United States. The attack is intended to constrain U.S. decision making, disrupt military deployment, and impose strategically relevant costs on the civilian populace. We aggregate CIs into seven classes to demonstrate how an attack on any one of these categories can have outsized effects because of interdependencies between infrastructure assets, systems, and networks. Because of the interconnected nature of CI systems, damage to one system can adversely affect another. This may lead to a cascading hazard, producing disruptions across geographic boundaries and CIs. We draw on reports of recent attacks on U.S.CI systems to inform our case study. These real-world events demonstrate interdependencies, probable effects, and challenges that could arise from future potential adversarial action targeting infrastructure in the homeland. Finally, we recommend actions to reduce the likelihood and severity of disruptions to U.S. CI in the event of attacks by a capable adversary.