As long as the parked vehicle is parked properly and not illegally parked in any manner, then the vehicle that rear-ended the parked car is at fault. Now if the parked car is sitting illegally (such as double parked or parked in a no parking zone, etc.) then the parked car is at fault or even both the parked car AND the car that hits it are BOTH at fault.

Parked was created in 2011.

It would be the car who had parked illegally because he was not parked in a legal spot.

I parked my car in the driveway