Weak encryption in Tesla Model S key fobs allowed all-too-easy theft, but you can set a PIN code on your Tesla to protect it.
Any key-fob (and their connected car) made prior to June are vulnerable to the weak encryption attack. There’s nothing particularly fancy about the attacks, watch the Nicholas Cage classic “Gone in 60 seconds” and you essentially see them do the same thing on a garage remote (from memory).
Telsa introduced a new PIN feature in an update a couple of weeks ago. That plugs the hole for now but Tesla haven’t really told their customers about the dangers in not setting a PIN in detail.
Another solution for car owners is to buy a new key-fob. That’s a cost though and considering Tesla knew of the hack a year ago (and paid a US$10k bug bounty for it) you’d hope they start a program to swap out old for new – at a reduced cost at least!