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The director of the FBI offered new evidence today to explain why the U.S. believes North Korea launched the cyberattack against Sony. James Comey spoke at a conference on cybersecurity in New York. When the FBI first accused North Korea last month, many technology experts were skeptical. NPR's Dina Temple-Reston reports on the FBI's latest effort to prove its case.
DINA TEMPLE-RASTON, BYLINE: The FBI director revealed newly declassified information that explained the link between North Korea and the Guardians of Peace, the group that claimed responsibility for the attack.
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JAMES COMEY: The Guardians of Peace would send emails threatening Sony employees and would post online various statements explaining their work. In nearly every case they used proxy servers to disguise where they were coming from, but several times they got sloppy.
TEMPLE-RASTON: Comey said that the hackers sometimes either forgot to disguise themselves or had a technical problem, so U.S. authorities could see them.
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COMEY: And we could see that IP addresses that were being used to post and to send the emails were coming from IPs that were exclusively used by the North Koreans. It was a mistake by them that we haven't told you about before that was a very clear indication of who was doing this.
TEMPLE-RASTON: Comey said the hackers would disconnect very quickly once they realized their mistake, but they were visible long enough for the U.S. to identify them.
MARK ROGERS: But there's certainly interesting information there that does support the fact that it could have been North Korea.
TEMPLE-RASTON: That's Mark Rogers, the principle security researcher at CloudFlare, an Internet security company.
ROGERS: But the problem is none of it conclusively says that it was North Korea and none if it conclusively rules out any other actors either.
TEMPLE-RASTON: And he says the FBI needs to be even more transparent.
ROGERS: Give us a little bit more to go on because right now it's just raising more questions than it is answering.
TEMPLE-RASTON: The FBI director hinted that there would be more details to come. In particular, details on how the hackers got into the Sony servers in the first place. Rogers said details about that would go a long way toward convincing skeptics like him who was behind this. Dina Temple-Reston, NPR News, New York.