The next step in international cyber-warfare?

There is a really interesting article out right now about the possibility of a water processing plant's computers having been hacked and shutting down the plant last week: U.S. probes cyber attack on water system (Reuters) - "Federal investigators are looking into a report that hackers managed to remotely shut down a utility's water pump in central Illinois last week, in what could be the first known foreign cyber attack on a U.S. industrial system." If true, this is some pretty fascinating, international infighting and leaves to many, many questions. The first being who would have done it. Would it have been the Chinese? Soviet Union? Someone else? A random hacker somewhere in the world? And then is whoever did it just "fishing", so to speak, to see if they could get away with this, in possible preparation for a far larger strike? Is the system the water treatment plant on Microsoft? If so, should all plants automatically get off it if they haven't already? How vulnerable are we all, around the world, let alone the US? It seems that all the nations in the world should get together, maybe through the UN, and declare that we won't do this to one another except it looks like the "Stuxnet" virus makes that moot. These are fascinating times we live in. I hope it doesn't get too "fascinating." Link: http://news.yahoo.com/u-investigates-cyber-attack-water-system-201719205.html