Hacking your car
This is nothing new of course. Remember twenty years ago your server's SMTP port was wide open and allowed forwarding - as a courtesy to other internet users.
Then it became too easy for people to get on the internet, and cheap Linux servers made it easy to talk SMTP. SPAM proliferated, and so we had to lock-down our services from the unwashed masses.
It seems the nodes on your CAN bus need certs and an encrypted channel. It's not a surprise. It should have been factored into the evolution of the incar electronics network. Of course, it's not that appealing to admit you need to beef up the CPUs in the nodes on the bus. That adds cost and reduces the benefit of going with such an interconnect system.
While we're thinking about these things, let's not forget the "internet of things" we're building out in our homes. When someone is telling you "These things are really cheap! You can put a computer in a light switch for a few pennies.", they probably aren't giving any though to security.