The big question for Norway, as they say, is "who is behind it?". The big question for all of us is how commonplace this is. It seems like it's easy enough to do, and law enforcement etc. don't seem to be looking for it actively/publicly.
Of course, there are also countries outside of NATO capable of orchestrating such an activity. In that case the chances increase that we'll soon hear much more.
Finally, with the greatest probability, the different devices can belong to many different entities, both "allies" and "foes" so it can be tricky, but doable, to talk about only some of them. That's why they've officially just "found something" at the moment.