You could make a "drive by" (in the literal sense) gizmo that bricks vulnerable cars, maybe even causes expensive physical damage. Can you start a car fire by controlling fuel pressure pumps and injectors, or destroy a turbocharger? Stick a ten minute delay in your injected code and you're long gone.
GM (or really, virtually any car manufacturer with the possible exception of Tesla) would be caught flat-footed.
Firmware in consumer products (especially where radio or network access is present) needs to have a security model. Car makers have been betting they didn't need to spend much money worrying about security; it doesn't look like that bet is going to pay off.
If this becomes a thing that any kid with $30 of electronics can do, dinosaur makers are toast.
I hate to break it to you, but any kid with USD 0.10 can start a fire in a car today. It requires a.) one rock and b.) one box of matches. Break a window with the rock, then throw lit matches onto the upholstery. Really, the threat model is NOT disaffected kids.
GM (or really, virtually any car manufacturer with the possible exception of Tesla) would be caught flat-footed.
Firmware in consumer products (especially where radio or network access is present) needs to have a security model. Car makers have been betting they didn't need to spend much money worrying about security; it doesn't look like that bet is going to pay off.
If this becomes a thing that any kid with $30 of electronics can do, dinosaur makers are toast.