On synergies of cyber and physical security modelling in vulnerability assessment of railway systems

Abstract

The multifaceted nature of cyber-physical systems needs holistic study methods to detect essential aspects and interrelations among physical and cyber components. Like the systems themselves, security threats feature both cyber and physical elements. Although to apply divide et impera approaches helps handling system complexity, to consider just one aspect at a time does not provide adequate risk awareness and hence does not allow to design the most appropriate countermeasures. To support this claim, in this paper we provide a joint application of two model-driven techniques for physical and cyber-security evaluation. We apply two UML profiles, namely SecAM (for cyber-security) and CIP_VAM (for physical security), in combination. In such a way, we demonstrate the synergy between both profiles and the need for their tighter integration in the context of a reference case study from the railway domain.

Flow-based Physical Security

“…In the case study, by correlating physical and logical credentials, the CPP Server recognizes the intrusion and activates cyber-countermeasures such as notification to the control room [6]. Figure 13 shows the FM representation of this scenario.…”

“…al., [6] describe a lineside shelter protection system where shelters are small buildings located along railway tracksides. The shelter is accessed by a door controlled by an Access control device (e.g., a card reader).…”

“…Figure 12 depicts the annotated UML Sequence Diagram illustrating the behavior of an Insider Threat scenario. In the annotated UML diagrams, a transformation generates yet another diagramming-based model suitable for evaluating the success probability of an attack [6]. International Journal of Security and Its Applications Vol.…”

“…A recent trend in security is to use top-down model-driven approaches including UML profiles for multifaceted security for cyber-physical systems needs [6]. " [S]ecurity of critical infrastructures… is a multi-faceted problem that requires an integrated approach taking into account digital (i.e., cyber) security as well as physical security, which is strictly related to system protection against intentional threats of [a] physical nature" [6].…”

“…[S]ecurity of critical infrastructures… is a multi-faceted problem that requires an integrated approach taking into account digital (i.e., cyber) security as well as physical security, which is strictly related to system protection against intentional threats of [a] physical nature" [6].…”