Structure and Function of Interconnected Critical Infrastructures

This paper presents ongoing research to understand the interplay between the structure and behavior of critical infrastructure systems. The National Infrastructure Protection Plan (NIPP), Presidential Policy Directive 21 (PPD 21), and other documents underscore the need to conduct risk assessments on critical infrastructure and discover high-risk assets. Complicating this problem however, is that interdependencies that aren’t explicitly modeled as part of the system can be important and greatly impact the system being studied. For example, the reported BadBIOS attack illustrates that through unexpected interactions (e.g. inaudible sounds), systems thought to be air-gapped may communicate with one another. Moreover, the impact of a disruption may be defined relative to some spatial or temporal scale and this may not always be explicit in a risk assessment. By combining graph complexity metrics with simulation, we hope to efficiently identify critical assets as well as understand more about the relationship between structure and function with critical infrastructure systems. This paper presents preliminary results from the electrical power grid as part of our ongoing research effort.