Illustration of Cybersecurity and Safety Co-Engineering using EBIOS RM and IEC 61508

Abstract

Risk analyses of complex Cyber-Physical Systems represent a persistent challenge both in Functional Safety and in Cybersecurity. Those two domains traditionally conduct their risk analyses independently. However, that independence is now questioned. The emergence of Cybersecurity risks with Safety impacts, such as killwares, acts as a serious incentive to evolve conventional methods and risk cultures. The objective of this article is to define the potential links between Functional Safety and Cybersecurity risk analyses. To that end, we made our Safety and Cybersecurity teams work on two use cases and exchange their opinions on their respective methods: HARA in Safety and EBIOS RM in Cybersecurity. In the first use case, the Cybersecurity team studies with the EBIOS RM a safety-related function : the Safe Remote Control (SRC). In the second use case, the Safety team presents a SIL assessment for SRC to the Cybersecurity team which identifies parameters to influence. Through those activities, both teams identify several points of divergence and challenges to deal with in order to enrich Cybersecurity/Safety approaches.