Sony Pictures' internal network remains down following November's GoP attack

Sony claims hack hasn't affected operations at the film studio as staff go offline to get work done

Sony Pictures Entertainment CEO Michael Lynton has admitted that the company's internal network remains down following the hack at the end of November, which saw emails, social security numbers and sensitive internal documents - as well as films and film scripts - released to the public.

"They came in the house, stole everything, then burned down the house," Michael Lynton, the movie studio's CEO, said in an interview with the Associated Press. "They destroyed servers, computers, wiped them clean of all the data and took all the data."

The company's internal network is expected to remain down for a few more weeks as forensic and other security specialists examine every server and PC for evidence of who was behind the attack.

In addition to bringing boxes of old BlackBerrys out of retirement so that management could communicate securely with each other, an emergency notification system was set up and information disseminated to staff via emergency "town hall" meetings.

Staff that weren't already on it were signed up to the Everbridge emergency notification system, while senior management created text message and "phone trees" to spread information. "Thirty to 40 people worked day and night through the Thanksgiving holiday. When employees arrived to work on Monday, one week after the Nov. 24th hack, a 'concierge'-like desk greeted them to help get them signed onto a temporary email system set up by the technology team," according to AP.

The FBI and security investigators Mandiant were brought in in the first week as soon as the scale of the attack became clear, with the FBI bringing in specialists to conduct "clinics" with staff covering identify theft - and, perhaps belatedly, computer security.

The hacking group Guardians of Peace (GoP) claimed responsibility for the attack - although the FBI is adament that the government of North Korea is ultimately responsible - and added that they had done it in response to the film The Interview, a comedy film depicting the fictional assassination of the North Korean leader Kim Jong-un.

Lynton also made a personal call to Google chairman Eric Schmidt, who jumped at the chance to sell The Interview on Google Play and YouTube. The film was also released on Microsoft's Xbox network and Apple's iTunes. According to Sony, The Interview is the most successful digital release it has had so far, with the film being watched over the internet around 4.3 million times. It has taken about $31m in receipts so far against a cost of production of about $40m.

Lynton claims that most of the security forensics and network rebuilding has been done and that email ought to get back up-and-running within a week and the rest of the network within two weeks.