Normally there are two _separate_ CAN busses, one which handles all the critical crap, and one which handles the infotainment and comfort stuff. There's a module which connects the two, providing read-only queries from the second to the first. None of the hacks breached this system.
Oh really? Then how did that Jeep Cherokee hack via the infotainment system work?
from http://www.wired.com/2015/07/h... (emphasis mine)
As the two hackers remotely toyed with the air-conditioning, radio, and windshield wipers, I mentally congratulated myself on my courage under pressure. That's when they cut the transmission.
Immediately my accelerator stopped working. As I frantically pressed the pedal and watched the RPMs climb, the Jeep lost half its speed, then slowed to a crawl. This occurred just as I reached a long overpass, with no shoulder to offer an escape. The experiment had ceased to be fun.