# Bus We only speak about the **CAN** bus to take an example, because the different attacks on bus like _FlewRay_, _ByteFlight_, _Most_ and _Lin_ use retro engineering and the main argument to improve their security is to encrypt data packets. We just describe them a bit: - **CAN**: Controller Area Network, developed in the early 1980s, is an event-triggered controller network for serial communication with data rates up to one MBit/s. **CAN** messages are classified over their respective identifier. **CAN** controller broadcast their messages to all connected nodes and all receiving nodes decide independently if they process the message. - **FlewRay**: Is a deterministic and error-tolerant high-speed bus. With a data rate up to 10 MBit/s. - **ByteFlight**: Is used for safety-critical applications in motor vehicles like air-bags. Byteflight runs at 10Mbps over 2 or 3 wires plastic optical fibers. - **Most**: Media Oriented System Transport, is used for transmitting audio, video, voice, and control data via fiber optic cables. The speed is, for the synchronous way, up to 24 MBit/s and asynchronous way up to 14 MBit/s. **MOST** messages include always a clear sender and receiver address. - **LIN**: Local Interconnect Network, is a single-wire subnet work for low-cost, serial communication between smart sensors and actuators with typical data rates up to 20 kBit/s. It is intended to be used from the year 2001 on everywhere in a car, where the bandwidth and versatility of a **CAN** network is not required. Domain | Tech name | Recommendations ---------------------------------- | --------- | -------------------------------------------------------------------------- Connectivity-BusAndConnector-Bus-1 | CAN | Implement hardware solution in order to prohibit sending unwanted signals. See [Security in Automotive Bus Systems](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.92.728&rep=rep1&type=pdf) for more information. # Connectors For the connectors, we supposed that they were disabled by default. For example, the **USB** must be disabled to avoid attacks like BadUSB. If not, configure the Kernel to only enable the minimum require **USB** devices. The connectors used to diagnose the car like **OBD-II** must be disabled outside garages. Domain | Tech name | Recommendations ----------------------------------------- | --------- | ---------------------------------------------------------------------- Connectivity-BusAndConnector-Connectors-1 | USB | Must be disabled. If not, only enable the minimum require USB devices. Connectivity-BusAndConnector-Connectors-2 | USB | Confidential data exchanged with the ECU over USB must be secure. Connectivity-BusAndConnector-Connectors-3 | USB | USB Boot on a ECU must be disable. Connectivity-BusAndConnector-Connectors-4 | OBD-II | Must be disabled outside garages.