At the Black Hat security conference last year in Las Vegas, iSec Partners security consultants Don Bailey and Matthew Solnik hacked a Subaru Outback using a cellular network. They were able to unlock the car and even start its engine. Bailey said that he and Solnik took about 2 hours to figure out how to intercept wireless messages between the car and the network and then re-create the messages from his laptop.

via Self-driving cars could bring a new world of hacking | TechHive.