--- /dev/null
+---
+edit_link: ''
+title: Bus and connectors
+origin_url: >-
+ https://raw.githubusercontent.com/automotive-grade-linux/docs-sources/master/docs/security-blueprint/part-7/1-BusAndConnectors.md
+---
+
+<!-- WARNING: This file is generated by fetch_docs.js using /home/boron/Documents/AGL/docs-webtemplate/site/_data/tocs/architecture/master/security_blueprint-security-blueprint-book.yml -->
+
+# 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.
+
+On just about every vehicle, **ECU**s (**E**lectronic **C**ontrol **U**nits)
+communicate over a CAN bus, which is a two-wire bus using hardware arbitration
+for messages sent on the shared medium. This is essentially a *trusted* network
+where all traffic is visible to all controllers and any controller can send any message.
+
+A malicious **ECU** on the CAN bus can easily inject messages destined for any
+other device, including things like the instrument cluster and the head unit.
+There are common ways for hardware to do USB to CAN and open source software to send
+and receive messages. For example, there is a driver included in the Linux kernel
+that can be used to send/receive CAN signals. A malicious device on the CAN bus can
+cause a great number of harmful things to happen to the system, including: sending
+bogus information to other devices, sending unintended commands to ECUs,
+causing DOS (Denial Of Service) on the CAN bus, etc.
+
+<!-- section-config -->
+
+Domain | Tech name | Recommendations
+---------------------------------- | --------- | --------------------------------------------------------------------------
+Connectivity-BusAndConnector-Bus-1 | CAN | Implement hardware solution in order to prohibit sending unwanted signals.
+
+<!-- end-section-config -->
+
+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.
+
+<!-- section-config -->
+
+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.
+
+<!-- end-section-config -->
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