The USA and Israel are reported to have released Stuxnet malware in Iran and did not intend the malware to escape a secure network. It did and now the world knows that USA has declared war via malware. The problem for the USA is that this strategy will backfire. Not only will a malware-arms-race develop but USA, being huge in IT and largely a monoculture of that other OS is ripe for the picking.
Malware has been shown to be effective and cheap at copying information/secrets/passwords, fraud, and other crimes but, in war, nothing prevents participants from going further, sabotaging IT. Combatants can plant IT bombs to go off at precisely-defined times to do the most damage. Think erased hard-drives, modified messages, bit-rot, DDOS, and all that. If the USA is not yet tired of war they certainly are doing their best to provoke another waste of resources. They will do more harm to themselves than all the terrorists have ever done in history, and they are virtually defenceless because hundreds of millions of PCs use x86 and XP or “7”. The USA has painted a bull’s eye on its back.