FBI assures doubters N. Korea hacked Sony: They 'got sloppy'

Kaja Whitehouse | USA TODAY

FBI Director James Comey sought to reassure doubters that the agency has solved the infamous cyberattack on Sony Pictures Entertainment with a tidbit of new evidence on Wednesday.

Speaking at a cybersecurity conference in Manhattan, Comey said Sony's hackers, who called themselves Guardians of Peace, usually went through proxy servers to hide their identity, but occasionally failed to follow through with this precaution.

The hackers "got sloppy" when sending e-mails and posting online, Comey said. This allowed the feds to trace them to IP addresses "exclusively used by the North Koreans," Comey said.

Last month, the FBI said North Korea was behind the attack, which forced Sony to temporarily halt plans to release The Interview, a satirical movie with James Franco and Seth Rogen about North Korean leader Kim Jong Un.

Since then, doubters have come out of the woodwork to blast the FBI for not providing enough evidence to link the attack to North Korea. Some respected cybersecurity experts have even put forth alternative theories — pointing the finger at Russia, for example.

"I know that some serious folks have suggested we have it wrong," Comey said. "They don't have the facts that I have. They don't see what I see."

"I have very high confidence about this attribution," he said.