“Asked about the possibility of using military force after a cyber assault, James Miller, undersecretary of defense for policy, said: ‘Yes, we need to think about the potential for responses that are not limited to the cyber domain.’

But he said it remained unclear what constituted an act of war in cyberspace.

‘Those are legal questions that we are attempting to address,’

Miller said at a conference in Washington, adding that ‘there are certainly a lot of grey areas in this field.’

He said hostile acts in cyberspace covered a wide range, from digital espionage to introducing false data into a network, that did not necessarily represent full-blown war. “

(Source: Pentagon says military response to cyber attack possible – Times LIVE.)