SINGAPORE U.S. defence systems are constantly under attack in cyberspace and the Pentagon is working to identify hackers who will be responded to in kind or with traditional offensive action, Defence Secretary Robert Gates said on Saturday.
Gates was speaking at the Shangri-La Dialogue, an Asian security meeting, days after Google said it had disrupted a campaign aimed at stealing passwords of hundreds of Google email account holders, including senior U.S. government officials, Chinese activists and journalists.
It was the latest in a series of cyber attacks that have also targeted defence contractor Lockheed Martin and Sony Corp. Google said the latest breach appeared to originate in China but neither the company nor the U.S. government has said the Chinese government was responsible.
But the U.S. State Department has asked Beijing to investigate.
"We take the cyber threat very seriously and we see it from a variety of sources, not just one or another country," Gates said.
"One of the problems of cyber attacks is that attributability is a problem at some times. It's hard to know or takes a lot of time to figure out where an attack came from."
Gates said the Pentagon was examining threats from cyber-space in the context of defence responsibilities.
"There is no question that our defence systems are under attack all the time," he said.
"What does constitute an offensive act by a government? What would constitute an act of war by cyber that would require some kind of response, either in kind or kinetically?" he said.
"We could avoid some serious international tensions in the future if we could establish some rules of the road as early as possible to let people know what kinds of attacks are acceptable, what kinds of acts are not and what kinds of acts may in fact be acts of war."
(Reporting by Raju Gopalakrishnan; Editing by Sanjeev Miglani)