Securing Vehicle Communication

Vehicle diagnostic operations often involve a technician connecting a vehicle diagnostic adapter to a diagnostic port in a vehicle. This is an authorized and trusted connection but it expands the vehicle system of interest to include the vehicle diagnostic adapter, the PC-based communications system, theoperating system, the middleware, and the diagnostic application. Therefore, the technician’s diagnostic computer system is part of the vehicle system, and securing diagnostic operations is necessary to improve the overall cybersecurity posture of the vehicle system. A device driver shim DLL attack on the communication stack for a vehicle diagnostics adapter is presented as an attack vector, followed by an example implementation of secured diagnosticsover a Unified Diagnostic Services (UDS) session. The security example is demonstrated on a contemporary engine electronic control unit (ECU) with engineering-level access to both the firmware running on the ECU and the diagnostic service tool. The example demonstrates the efficacy of utilizing UDS service $84 to secure diagnostics communication and its impact on computational overhead and network speed. The approach is extended to the Universal Measurement and Calibration Protocol (XCP), which does not yet have recommended security approaches. Since vehicle diagnostics and service computers are provided by a third party, they should not be inherently trusted, and to improve the security posture of vehicle systems, critical diagnostics communications should have security controls.