According to the U.S. Strategic Command, the Department of Defense (DOD) is in the midst of a global cyberspace crisis as foreign nation states and other actors, such as hackers, criminals, terrorists, and activists exploit DOD and other U.S. government computer networks to further a variety of national, ideological, and personal objectives. This report identifies (1) how DOD is organized to address cybersecurity threats; and assesses the extent to which DOD has (2) developed joint doctrine that addresses cyberspace operations; (3) assigned command and control responsibilities; and (4) identified and taken actions to mitigate any key capability gaps involving cyberspace operations. It is an unclassified version of a previously issued classified report. GAO analyzed policies, doctrine, lessons learned, and studies from throughout DOD, commands, and the services involved with DOD's computer network operations and interviewed officials from a wide range of DOD organizations.