North Korea denounces The Interview and happy to be on the list of suspects

North Korea has refused to deny it was behind a cyber-attack a week ago that resulted in online leaks of several new Sony Pictures films, possibly in retaliation for a forthcoming Sony film depicting a fictional plot to assassinate Kim Jong-un.

The attack leaked at least five high-profile titles – the recently released Fury, as well as unreleased movies such as Still Alice, Annie and To Write Love On Her Arms – to file-sharing sites and crippled the firm’s corporate email and other parts of its internal network.

The Interview, a comedy due for release next month about two journalists who are hired by the CIA to assassinate Kim, was not leaked. There has been speculation that the North, perhaps using hackers based in China, was trying to get its retaliation in early.

Despite reports that North Korea has assembled a sophisticated cyber-attack unit, and similarities between the Sony hack and a cyber-attack on South Korean banks and TV networks last year, experts say little hard evidence exists to point to the secretive state.

But North Korean officials appeared happy to let their country stay on the list of suspects. Asked whether Pyongyang was involved in the attack, a spokesman for North Korea’s mission to the UN accused “hostile forces” – usually a reference to the US, South Korea and Japan – of blaming everything on the North. But he added: “I kindly advise you to just wait and see.”

The FBI said it was investigating the hack and did not name any suspects.

Pyongyang reacted angrily when the film’s plot became public this summer, and promised a “resolute and merciless” response unless the US banned it. North Korea’s ambassador to the UN, Ja Song-nam, called the movie “the most undisguised sponsoring of terrorism as well as an act of war”, in a letter to the UN secretary general, Ban Ki-moon.

Re/code, a technology news website, was the first to float the North Korea theory last Friday. Citing unnamed sources familiar with the matter, it said: “Sony Pictures Entertainment is exploring the possibility that hackers working on behalf of North Korea, possibly operating out of China, may be behind a devastating attack that brought the studio’s network to a screeching halt earlier this week … The sources stress that a link to North Korea hasn’t been confirmed, but has not been ruled out, either.”

Last week employees at Sony Pictures were greeted with an image of a red skull on their computer screens and the message “Hacked by #GOP” – thought to stand for Guardians of Peace. The screens then went dark.

Sony Pictures said it was trying to establish who was behind the attack. “The company has restored a number of important services to ensure ongoing business continuity and is working closely with law enforcement officials to investigate the matter,” it said.

It is not the first time North Korea has been accused of mounting cyber-attacks. While most ordinary North Koreans have no access to computers or the internet, the regime is thought to have committed vast resources to the development of a cyber-warfare unit.

Last year North Korean hackers were blamed for paralysing computer networks at three South Korean banks and the country’s two biggest TV networks. Some observers have noted that the methods used in that attack were similar to those used against Sony.

But Martyn Williams, of North Korea Tech, said that was where the similarities ended. In a blogpost on Tuesday, Williams lists several inconsistencies between the Sony incident and previous cyber-attacks linked to North Korea. They included the targeting of the Sony chief executive, Michael Lynton, on Sony Twitter accounts and the claim that the hack was carried out by the Guardians of Peace.

“Attacks linked to North Korea have never included these credits,” Williams said. “Of course none of these mean that the country is definitely not involved, but it seems possible that the story is too good to be true.”

In The Interview, which is due for release in the US on Christmas Day, Seth Rogen and James Franco play celebrity TV journalists who secure an exclusive interview with Kim and are then recruited by the CIA to kill him. A trailer of the film reveals a less than flattering portrayal of Kim, played by Randall Park, as an overweight cigar smoker.

Having once said he hoped Kim would like the movie, Rogen’s tone had hardened by last weekend. “I personally don’t care if [THE FILM IS]disrespectful to Kim because he’s evil. But that’s not the intent,” he tweeted on Sunday. “North Korea has produced tons of propaganda films that portray America’s destruction.