ANNAPOLIS, Md. (April 15,2015) U.S. Naval Academy Midshipmen work together during last year’s Cyber Defense Exercise hosted by the National Security Agency. A new report from the Government Accountability Office finds the Defense Department’s chain of command is unclear for responding to domestic cyber attacks. (U.S. Navy photo by Mass Communications Specialist 2nd Class Tyler Caswell/RELEASED)(Photo: Navy Media Content Services)