Biblio
Cyber security risk assessment is very important to quantify the security level of communication-based train control (CBTC) systems. In this paper, a methodology is proposed to assess the cyber security risk of CBTC systems that integrates complex network theory and attack graph method. On one hand, in order to determine the impact of malicious attacks on train control, we analyze the connectivity of movement authority (MA) paths based on the working state of nodes, the connectivity of edges. On the other hand, attack graph is introduced to quantify the probabilities of potential attacks that combine multiple vulnerabilities in the cyber world of CBTC. Experiments show that our methodology can assess the security risks of CBTC systems and improve the security level after implementing reinforcement schemes.
To meet the growing railway-transportation demand, a new train control system, communication-based train control (CBTC) system, aims to maximize the ability of train lines by reducing the headway of each train. However, the wireless communications expose the CBTC system to new security threats. Due to the cyber-physical nature of the CBTC system, a jamming attack can damage the physical part of the train system by disrupting the communications. To address this issue, we develop a secure framework to mitigate the impact of the jamming attack based on a security criterion. At the cyber layer, we apply a multi-channel model to enhance the reliability of the communications and develop a zero-sum stochastic game to capture the interactions between the transmitter and jammer. We present analytical results and apply dynamic programming to find the equilibrium of the stochastic game. Finally, the experimental results are provided to evaluate the performance of the proposed secure mechanism.