Biblio

The Controller Area Network (CAN), a broadcasting bus for intra-vehicle communication, does not provide any security mechanisms, although it is implemented in almost every vehicle. Attackers can exploit this issue, transmit malicious messages unnoticeably and cause severe harm. As the utilization of Message Authentication Codes (MACs) is only possible to a limited extent in resource-constrained systems, the focus is put on the development of Intrusion Detection Systems (IDSs). Due to their simple idea of operation, current developments are increasingly utilizing physical signal properties like voltages to realize these systems. Although the feasibility for CAN-based networks could be demonstrated, the least approaches consider the constrained resource-availability of vehicular hardware. To close this gap, we present Voltage-Based Lightweight Intrusion Detection (VALID), which provides physics-based intrusion detection with low resource requirements. By utilizing solely the individual voltage levels on the network during communication, the system detects unauthorized message transmissions without any sophisticated sampling approaches and feature calculations. Having performed evaluations on data from two real vehicles, we show that VALID is not only able to detect intrusions with an accuracy of 99.54 %, but additionally is capable of identifying the attack source reliably. These properties make VALID one of the most lightweight intrusion detection approaches that is ready-to-use, as it can be easily implemented on hardware already installed in vehicles and does not require any further components. Additionally, this allows existing platforms to be retrofitted and vehicular security systems to be improved and extended.

Increased connectivity increases the attack vector. This also applies to connected vehicles in which vulnerabilities not only threaten digital values but also humans and the environment. Typically, attackers try to exploit the Controller Area Network (CAN) bus, which is the most widely used standard for internal vehicle communication. Once an Electronic Control Unit (ECU) connected to the CAN bus is compromised, attackers can manipulate messages at will. The missing sender authentication by design of the CAN bus enables adversarial access to vehicle functions with severe consequences. In order to address this problem, we propose Scission, an Intrusion Detection System (IDS) which uses fingerprints extracted from CAN frames, enabling the identification of sending ECUs. Scission utilizes physical characteristics from analog values of CAN frames to assess whether it was sent by the legitimate ECU. In addition, to detect comprised ECUs, the proposed system is able to recognize attacks from unmonitored and additional devices. We show that Scission is able to identify the sender with an average probability of 99.85%, during the evaluation on two series production cars and a prototype setup. Due to the robust design of the system, the evaluation shows that all false positives were prevented. Compared to previous approaches, we have significantly reduced hardware costs and increased identification rates, which enables a broad application of this technology.