[nacs]

It's a wired-ethernet network not Wifi.

The attacker would still need physical access like the low-tech attacker to network and update software on the Tesla.

Also, the brake line could be cut in seconds whereas 'jailbreaking' and then flashing the drive control software would take ages in comparison.

[munin]

yeah but the state police can examine a crash after the fact to determine a brake line was cut.

even if the software survives a high-speed crash, it's possible for the surreptitiously placed modification to erase itself as its final act. additionally, the surreptitiously placed modification can wait for weeks or months, giving the attacker time to build a cover story or misdirect or accomplish any number of other goals.