Believe it when you see it. The press is throwing cyber war warnings everywhere it can. . . most of them are quite unimportent. These threats always come to effectively nothing, even when the CIA or FBI issues them.
Remember, if it was that easy, it would be happening. It is that easy, and it is happening. Every day. Most of us don't notice. Sometimes a site we care about gets hacked; the backup tapes roll, the patches are applied, and life goes on. Threats of escalation are mostly empty posturing.