FBI lacks evidence North Korea to blame for Sony hack

An FBI official says the agency can't yet prove who was behind the devastating cyberattack on Sony.

The FBI can't yet prove who was behind the devastating Thanksgiving hack attack against Sony Pictures. FBI

The FBI still can't prove who was -- or wasn't -- behind last month's cyberattack on Sony Pictures, which led to the theft of thousands of documents and revealed confidential information about the company and its employees.

"There is no attribution to North Korea at this point," said Joe Demarest, assistant director of the Federal Bureau of Investigation's cyber division. Demarest was speaking Tuesday on a panel at a Bloomberg Government cybersecurity conference, in Washington, DC. His comments were later confirmed by the FBI.

This marks the first time anyone at the FBI has commented publicly on the agency's investigation into the attacks, and it may indicate the bureau is broadening its inquiry. The attack has been described by independent computer security company Mandiant as "unprecedented" because of the volume of Sony files stolen and the destruction of hard drives.

A previously unknown group of hackers broke in to computers inside Sony Pictures on November 24. The group, calling itself the Guardians of Peace, leaked financial documents, unreleased movies, confidential information about employees and celebrities, and details on the internal workings of Sony's computer security department in addition to leaving the department's computers unusable.

Circumstantial evidence had indicated that North Korea could be behind the hack. This included similarities between the malware used in this attack and an attack by North Korea against South Korean media companies and banks in 2013.

North Korea, which has denied allegations of its involvement, expressed support for the hack over the weekend.

"The hacking into Sony Pictures might be a righteous deed of the supporters and sympathizers with the DPRK [Democratic People's Republic of Korea]," a spokesman for North Korea said.

North Korean officials expressed outrage to the White House in July over the upcoming Sony comedy film "The Interview." The fictional piece focuses on an assassination attempt on North Korean leader Kim Jong-un.

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