2017-08-19

Controller Area Network (CAN) standard ISO 11898 data link vulnerability

Description

The Controller Area Network, CAN is the most common (in US the only legal) intravehicular databus standard ISO 11898-1993 for road vehicles. It allows all “Things” within the vehicle to communicate with each other. A university level research (Palanca and Zanero, 2016) has found that normal protocol at CAN link layer intended to handle malfunctioning nodes can be manipulated. 

Since the MILCAN (Open standard for military vectronics) is based on same ISO 11898, although rugged, there might be similar vulnerability within military vehicles (Majoewsky and Davies).

Case of exploitation

An attacker couples into CAN bus, receives the error frames, multiplies and forwards them further causing a Bus Off State to targeted subsystem. This means that targeted system is not listened anymore within the CAN bus i.e. the vehicle does not function as system of systems anymore. 

The coupling is easiest accomplished by connecting additional device into vehicle CAN bus. There is also possibility to use some wireless devices attached to CAN bus. In civilian vehicles, this may happen through Infotainment devices (radio, mobile phone) as happened in Chrysler Jeep hacking 2015 (Miller and Valasek). In military vehicles the vectronics is used more widely to connect sensors, weapons and C3 systems to vehicle. Thus, direct ways to effect the bus are available. Would there be one worm that can take down the fleets of military vehicles when they are dearly needed?

Mitigation

There are no software updates available and since the vulnerability is in the standard protocol itself, it requires to be changed. There may be some technical mitigation measures as follows:
  • Network segmentation or topology alteration
  • OBD-II diagnostic port access
  • Encryption

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