Matthew Gault:

The auto industry standardized the CAN chips in 2007. Since then — with some small variations — every car’s little single-celled brain has been largely the same.
 Though car manufacturers are now adding fancy electronic upgrades such as Bluetooth access or OnStar, they merely added other CAN computers to a car to operate them. The CAN operating a car’s WiFi, for example, is separate from the CAN operating the transmission, but the two do communicate. Typically, the CAN running crucial components — like the brakes or engine — is read-only, meaning the car’s other computer systems shouldn’t be able to change or interfere with it.
 It turns out, however, that most car companies have done a terrible job of protecting the tiny brains at the heart of virtually all cars. The most dangerous car hacks succeed by hijacking the CAN controlling a car’s brakes, engines and transmission.