If we put several separate reports together, what we get is that the U.S. and Israel already are making undeclared war on Iran. Report 1 is from the Pentagon in which it classifies digital sabotage as an act of war. Report 2 is from CBS in which an expert says that the Stuxnet attack on Iran's uranium centrifuges was done by a government agency: "You're really looking at a government agency from some country who is politically motivated and who has the insider information from a uranium enrichment facility that would facilitate building a threat like this." The two possibilities are Israel and the U.S. (or both), since Israel has long had the uranium enrichment capability and has used it. Report 3 is from a Wikipedia article on Stuxnet. It contains a good deal of evidence that the U.S. and/or Israel launched the Stuxnet attack. Report 4 is that the U.S. will not deny that it is behind Stuxnet. This contrasts with its strong denial that it is behind the assassinations of Iranian nuclear scientists, leaving Israel as the culprit. Report 5 is that the New York Times already reported that the U.S. and Israel launched the Stuxnet attack.
Hence, according to the Pentagon's own policy that cyber attacks that are violent and involve sabotage are acts of war, the U.S. and Israel have already begun an undeclared war on Iran. (This doesn't exclude other acts such as assassinations and drones and munitions sabotage and covert operatives as also indicating an undeclared war has already begun.)