U.S. considers 'proportionate' response to Sony hacking attack

By David Brunnstrom WASHINGTON (Reuters) - The United States said on Thursday a cyber attack on Sony Pictures blamed on North Korea was a serious national security matter and the Obama administration was considering a proportional response. White House spokesman Josh Earnest told reporters the attack was an example of "destructive activity with malicious intent that was initiated by a sophisticated actor." Earnest said he was not in a position to say that North Korea was responsible, b