What does it mean to see an eagle attacking a squirrel in a dream?

Perhaps it doesn't really mean anything. It may be that you mind is capturing different images to entertain your brain when you're sleeping, but who knows for sure? It definitely isn't something which should worry you.

Then again, the squirrel in this dream symbolizes some person or problem that is causing trouble for you. It need not represent an actual "attack" in the sense of violence or ambush, but something more like an unexpected obstacle or resistance. The squirrel carries the sense of something that is "squirrel-ly," "nuts" or somehow illogical and silly. It is also a minor difficulty as opposed to a major problem.