There are some AI in works of fiction that you could describe as indifferent. The one in neuromancer for example just wants to talk to other AI in the universe and doesn't try to transform all resources on earth into material to run itself.

An AI that does try to grow itself like a cancer is on the other hand unfriendly.

If you take about something like the malaria virus we also wouldn't call the virus indifferent but unfriendly towards humans even if the virus just tries to spread itself and doesn't have the goal of killing humans.