Cyber Security Attributes for Critical Infrastructure Systems

Is it time to retire the CIA triad for critical infrastructure systems? Hugh Boyes investigates...

The UK’s Critical National Infrastructure (CNI) comprises a geographically and technically diverse range of complex cyber–physical systems that are necessary for the country to function and for operation of daily services upon which our daily lives depend. We take for granted that water will flow when we turn on a tap, that electricity is available when we turn on a switch and that food and fuel will be available when we want to buy them. We also expect emergency, financial and health services to be available when we need them. However they all rely on a predominantly privately owned and operated infrastructure, which is largely invisible to us. This infrastructure is becoming increasingly complex as the operators introduce greater automation and more sophisticated controls in response to environmental and economic pressures. These so called ‘smart’ systems, such as the Smart Grid, Smart Metering, Intelligent Transport, etc., rely heavily on the use of communications and information technologies to enable dynamic control in response to demand or consumption. Significant benefits will come where systems integration delivers operational gains, e.g., the production and storage of electricity from renewable sources. However, introduction of ‘smart’ technologies and greater integration of these systems is not without its risks, particularly those related to cyber security vulnerabilities.

This article examines the nature of cyber–physical systems and how they differ from the information processing systems used in administrative or banking functions. It discusses the limitations of the traditional information assurance ‘CIA’ triad when applied to these complex systems and illustrates how, with minor modifications, an alternative assurance model can be used to address both cyber security and systems safety.