This paper presents a cyber-physical systems modelling language for capturing and describing health-based critical infrastructures. Following this practice incident response plan developers are able to model and reason about security and recovery issues in medical cyberphysical systems from a security requirements engineering perspective. Our work builds upon concepts from the Secure Tropos methodology, where in this paper we introduce novel cyber-physical concepts, relationships and properties in order to carry out analysis of incident response plans based on security requirements. We illustrate our concepts through a case study of a radiological department's medical cyber-physical systems that have been infected with the WannaCry ransomware. Finally, we discuss how our modelling language enriches security models with incident response concepts, guiding plan developers of health-based critical infrastructures in understanding cyber-physical systems vulnerabilities and support decision making at a tactical and a strategic level, through semi-automated secure recovery analysis.

Security constraints that enforce security requirements characterize healthcare systems. These constraints have a substantial impact on the resiliency of the final system. Security requirements modelling approaches allow the prevention of cyber incidents; however, the focus to date has been on prevention rather than resiliency. Resiliency extends into the detection, mitigation and recovery after security violations. In this paper, we propose an enhanced at a conceptual level that attempts to align cybersecurity with resiliency. It does so by extending the Secure Tropos cybersecurity modelling language to include resiliency. The proposed conceptual model examines resiliency from three viewpoints, namely the security requirements, the healthcare context and its implementational capability. We present an overview of our conceptual model of a cyber resiliency language and discuss a case study to attest the healthcare context in our approach.

No abstract