Actually, there is. They tend to huff and puff about American military exercises that occur in cooperation with the Japanese or the South Koreans, or to complain to the UN about various things (e.g.: the CIA torturing people). But their MO, such as it is, is to complain and threaten, almost exclusively. Occasionally they will perform a missile test that causes concern, but those missiles land in the Sea of Japan or some other body of water, not anywhere that causes actual harm.

No, this goes against the DPRK's MO up until now. If they are responsible then it is a shift in their tactics from "loud and threatening, but basically harmless to other nations", to "actively and publicly committing acts of economic espionage." That would be quite a departure for them.