The railway industry—traditionally a conservative industry with low adaption speed for innovation—is currently entering its digitization phase. The sector faces a challenge in integrating new technologies and approaches into the employed—often safety-critical—systems. Keeping the systems secure while conforming to the demanding safety norms creates previously unknown problems. In the last decades, the number of attacks on the railway system has increased. Furthermore, with standardized digital technologies, the attack surface will keep growing. Therefore, in this work, we look into the foreseeable future of the railway system and present 21 likely use cases. We analyze these use cases regarding possible threats, rate the severity of these threats, and deduce and rate necessary countermeasures. To this end, we model these use cases and the corresponding threats and countermeasures using Attack Graphs. We use a graphical solution for the risk and security analysis due to advantages over other methods, i.e., table-based solutions, like simplified presentation and an easier understanding of relationships, dependencies, and interactions between various elements. From these Attack Graphs, we extracted 14 commonly recurring attack strategies. After analyzing 49 countermeasures regarding their current maturity and further research and standardization demands, we identified 21 in need of further investigation. This implies that 21 necessary countermeasures to secure these future use cases require further research to apply to railway systems or require standardization. These results will help researchers focus on the necessary research and standardization and railway operators to ensure the security of their systems.

Cybersecurity risk assessment is essential for ensuring the security and resilience of Operational Technology (OT) systems, which are increasingly targeted by cyber threats. Traditional assessment frameworks often struggle with complexity, inefficiency, and the inability to adapt dynamically to evolving attack scenarios. In this work, we propose a novel approach that utilizes Attack Graphs to systematically model and assess cybersecurity risks in OT environments. Attack Graphs provide a structured representation of attack paths, enabling a comprehensive analysis of vulnerabilities and potential adversary actions. We extend conventional Attack Graphs by integrating countermeasures and impact assessment, allowing for a more complete cybersecurity risk evaluation process. Our framework facilitates adaptive assessments by efficiently incorporating system or environmental changes and identifying the most critical security threats. We validate our approach through a case study, demonstrating its effectiveness in enhancing OT risk assessment and aligning it with established cybersecurity standards. By bridging the gap between theoretical cybersecurity risk assessment models and practical security challenges, our work contributes to a more proactive and structured defense strategy for OT systems.

Risk assessment plays a crucial role in ensuring the security and resilience of modern computer systems. Existing methods for conducting risk assessments often suffer from tedious and time-consuming processes, making it challenging to maintain a comprehensive overview of potential security issues. In this paper, we propose a novel approach that leverages attack graphs to enhance the efficiency and effectiveness of risk assessment. Attack graphs visually represent the various attack paths that adversaries can exploit within a system, enabling a systematic exploration of potential vulnerabilities. By extending attack graphs with capabilities to include countermeasures and consequences, they can be leveraged to constitute the complete risk assessment process. Our method offers a more streamlined and comprehensive analysis of system vulnerabilities, where system changes, or environment changes can easily be adapted and the issues exposing the highest risk can easily be identified. We demonstrate the effectiveness of our approach through a case study, as well as the applicability by combining existing risk assessment standards with our method. Our work aims to bridge the gap between risk assessment practices and evolving threat landscapes, offering an improved methodology for managing and mitigating risks in modern computer systems.

Risk assessment plays a crucial role in ensuring the security and resilience of modern computer systems. Existing frameworks for conducting risk assessments often suffer from tedious and time-consuming processes, making it challenging to maintain a comprehensive overview of potential security issues. In this article, we propose a novel approach that leverages Attack Graphs to enhance the efficiency and effectiveness of risk assessment. Attack Graphs visually represent the various attack paths that adversaries can exploit within a system, enabling a systematic exploration of potential vulnerabilities. By extending Attack Graphs with capabilities to include countermeasures and consequences, they can be leveraged to constitute the complete risk assessment process. Our framework offers a more streamlined and comprehensive analysis of system vulnerabilities, where system changes, or environment changes can easily be adapted, and the issues exposing the highest risk can easily be identified. We demonstrate the effectiveness of our approach through a case study, as well as the applicability by combining existing risk assessment standards with our framework. Our work aims to bridge the gap between risk assessment practices and evolving threat landscapes, offering an improved framework for mitigating risks in modern computer systems.