A Survey on Survivable Safety-Critical Systems

Safety-critical systems (SCS) are essential in domains such as automotive, railway, e-health, nuclear power, and air transportation, where failure can result in catastrophic consequences. Due to their crucial functions, these systems are frequent targets of various attacks, including Denial of Service (DoS) attacks, the execution of improper commands, code injection, and data manipulation, which can compromise system safety and put lives and critical infrastructure at risk. While numerous studies and surveys have investigated the security of SCS, they focus predominantly on recognition mechanisms and often neglect a broader and equally critical concept: survivability. This pioneering survey presents a comprehensive and systematic literature review on the survivability of SCS. It delves into the resilience of these systems in the face of adverse events, examining how they maintain essential services under attack. Our first contribution is the introduction of a novel taxonomy that comprehensively classifies existing survivability approaches based on application fields, types of attacks, survivability properties, and evaluation methodologies. This taxonomy serves as a foundational framework for researchers and practitioners, facilitating the systematic analysis and design of survivable SCS. Our second contribution is the proposition of the survivability by design paradigm, which advocates for the proactive incorporation of survivability considerations into the early stages of SCS development. This paradigm aims to support the holistic integration of preventive, reactive, and tolerant security mechanisms throughout the entire SCS engineering life-cycle, particularly in the context of next-generation networks.