Girl lives in woods with dad and calls their dog “Mom”

Recently have been thinking about a movie and it goes as such,
a young girl and her dad live in the woods alone with their dog that she calls “mom” the dog can talk due to a box and it’s kind of believed she’s the personality of the mom.

A teenage girl and her younger brother come by their house and the dad let’s them stay, they are murderers and the young girl finds clues to try to prevent them from being successful in killing her and her father. At the end of the movie the girl is unsuccessful and then runs deeper into the woods and crawls into a black box that opens when she touches it.