FBI: North Korea responsible for Sony hack North Korea is officially responsible for the cyber attack on Sony Pictures, the FBI announced Friday. An FBI investigation linked the malware, infrastructure and techniques a group of hackers called "Guardians of Peace" used in the Sony attack to previous North Korean cyber attacks. The North Korean-backed hackers broke into Sony's servers, published private emails and information and threatened to attack movie theaters screening "The Interview," a comedy film about an assassination plot on North Korean leader Kim Jong Un. The official report that North Korea was behind one of the largest and disruptive cyber attacks on a major company confirms what most already suspected throughout the past few weeks, though the larger question -- how will the United States respond -- remained unanswered. What's next? Is this the beginning of more cyber attacks and what should our response be?