Hack Your Car! - Episode 300 Pt.8 - August 31, 2012

Hack your Car with CANBUS

A little into in a few minutes. yes, as implied, it is a BUS and you can gain access to it from the ODB-II port. Think a hub. All messages on a segment go to all devices on the segment. Messages can be filtered with a gateway (think firewall) between various busses, which may or may not be exposed at the ODB-II port. A little bit different from networks that we are familliar with. First off, the message do not have source field, but do have a destination in the form of a one byte arbitration ID, these arbitration IDs also indicate priority - the lower the Arbitration ID destination, the higher priority the message. So the ArbID 0 would be processed prior to 73febeef. Now, each message is sent to the bus with an ArbID, and each device LISTENS for specific ArbIDs that is concerned about. With that, Gateways can pass specific messages, and each Device can look for multiple messages. Oh, those messages? Either 11 or 29 bytes, so fairly easy to fuzz.