Sony Hack: FBI Director Speaks About Evidence Pointing to North Korea

How the FBI figured out North Korea was responsible for unprecedented hack.

Speaking at the International Conference on Cyber Security at Fordham University today in New York City, Comey revealed for the first time that the FBI saw IP addresses previously used by North Korea.

"Some serious folks have suggested that we've got it wrong," he said, noting that there were other sources and methods he could not reveal but were used by the FBI in their investigation.

"There is not much in life I have high confidence about," Comey added, defending the conclusion of federal officials that North Korea was responsible for the attack. "I have very high confidence in that attribution"

Comey's remarks come just days after the United States levied new sanctions on North Korean officials and its defense industry.