Surely you don't expect the WP article to list every act that might be compatible with the idea of a "cold war"... I feel you are trolling a bit. Sabotage is still a plausibly deniable act--contrasted with, say, rolling a tank across one's adversary's border.

Stuxnet is a weapon of sabotage, it is fairly direct, and yet it is not the same as an open declaration of war.