Sources: North Korea Behind Sony Cyber-Attack

An investigation into the Sony (Swiss: SONC.SW - news) cyber-attack has determined North Korean government was behind the operation, the FBI has said.

The agency said a technical analysis of data deletion malware used in the Hollywood studio hack provided links to malware previously developed by North Korean actors.

A "significant overlap" existed between the infrastructure used in the Sony cyber-attack and the tools used in previous cyber activity by North Korea, the FBI said.

The Obama administration has called the devastating hack against Sony a serious national security matter.

US officials were expected on Friday to make a formal statement on the cyber-attack that led to a series of embarrassing leaks.

One official, who spoke on condition of anonymity, told Reuters the US probe revealed a possible Chinese link either through collaboration or through the use of Chinese servers.

China on Friday urged the US to share evidence

Sony Pictures on Wednesday cancelled the release of the comedy The Interview, which depicted a plot to assassinate North Korean leader Kim Jong-Un.

The decision to pull the film was made after the group claiming responsibility for the hack made terrorist threats against US cinemas that showed the movie.

The hackers, who call themselves Guardians of Peace, praised the decision to cancel the film's release in a statement provided to CNN on Friday.

The group also said it would keep Sony's data secure if the company continued to comply.

"It's very wise that you have made a decision to cancel the release of The Interview," the message said, according to CNN.

"We ensure the security of your data unless you make additional trouble."

On Thursday, White House spokesman Josh Earnest said the US considered the cyber-attack a serious national security matter and a "proportionate response" was being considered.

North Korea has previously denied involvement in the hack.

President Barack Obama is scheduled to speak to reporters later on Friday during his end-of-year news conference.

A host of Hollywood stars and film-makers have slammed the decision to cancel

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