A man walks by the poster for the film "The Interview" outside the Alamo Drafthouse theater in Littleton, Colorado December 23, 2014. Sony Pictures said on Tuesday it will release "The Interview" to a limited number of theatres on December 25. Photo by Reuters.
The hackers, who defined themselves as the group "Guardians of Peace" sometimes "got sloppy" and used servers only accessible by North Korea, Comey said at the International Conference on Cyber Security in New York.