US sees North Korea hand in Sony hack

The unprecedented hack of Sony Pictures, which according to a US official was linked to North Korea, might be the most damaging cyber attack ever inflicted on a US firm, Associated Press reported.

The fallout from the hack that exposed a trove of sensitive documents, which escalated this week to threats of terrorism, forced Sony to cancel release of the North Korean spoof movie The Interview. The studio's reputation suffered as embarrassing revelations spilled from tens of thousands of leaked emails and other company materials.

According to federal investigators there was a connection between the Sony hack and the isolated communist nation, an official spoke on condition of anonymity.

Though North Korea had denounced the "The Interview", earlier this month it said the hack might have been carried out by sympathisers.

The movie features a pair of journalists played by James Franco and Seth Rogen who are asked by the CIA to assassinate North Korean leader Kim Jong Un.

According to Avivah Litan, a cybersecurity analyst at research firm Gartner, the attack was possibly the costliest ever for a US company. She added, the attack went to the heart and core of Sony's business and succeeded, adding, an attack of the kind had not been seen in the annals of US breach history.

Meanwhile according to US officials, North Korea was ''centrally involved'' in the hacking of Sony Pictures computers, even as the studio canceled the release of a far-fetched comedy about the assassination of the North's leader that was believed to have led to the cyberattack, The New York Times reported.

According to senior administration officials, who would not speak on the record about the intelligence findings, the White House was debating whether to publicly accuse North Korea of what amounted to a cyberterrorism attack.

Sony capitulated after the hackers threatened additional attacks, perhaps on theatres themselves, in the event of the release of the movie.

According to officials it was not clear how the White House would respond, some within the Obama administration argue that the government of Kim Jong-un needed to be directly confronted.

That however, raised questions of what actions the administration could credibly threaten, or how much evidence to make public without revealing details of how it determined North Korea's culpability, which included the possible penetration of the North's computer networks.

According to other administration officials, a direct confrontation with the North would provide North Korea with the kind of dispute it coveted.