Defense against car hacking

The CAN bus handles communication among computers on vehicles.  It is a point of vulnerability because by law there is an external OBD connection (so backyard mechanics can work on their cars).  Identifying a malicious device hooked into the CAN is critical for automotive security.  A new technique has been proposed: each device on the CAN has a unique signature in its clock (called clock skew) that can be used to identify devices on the CAN.  Therefore, a new, previously unknown and likely malicious device can be identified. A summary appears here: https://www.wired.com/   This latest technique joins an earlier technique that identified the regular communication patterns of devices on the CAN allowing a new one to be identified (summary https://www.wired.com/)