US film and TV company Sony Pictures Entertainment has reportedly hired FireEye's Mandiant forensics team to clean up the damage from last week's cyber-attack.
Reuters reports that the information came from “three people with knowledge of the matter”, with one of these adding that the US Federal Bureau of Investigation (FBI) is now investigating the incident. Technicians are repairing the damage to the network and expect to have the email systems back online later today, according to the sources.
Last Monday, the company has hit by a blackmailing hacker attack which saw the attackers shut down IT systems and hijack Twitter accounts, while confidential documents and passwords were also thought to have been stolen. In addition, new information over the weekend suggests that five unreleased Sony-made films were leaked onto file-sharing websites.
The computer systems displayed the message ‘Hacked by #GOP', which is believed to stand for the so-called Guardians of Peace. The group said that it would release the company's ‘top secret data' if its demands were not met.
Sony, FireEye and the FBI all declined to comment.
Meanwhile, technology news website Re/Code reported over the weekend that Sony is investigating to determine whether hackers were working on behalf of the North Korean government.
The attack is believed to be in retribution to the studio's backing of the film ‘The Interview', a comedy about a CIA attempt to assassinate North Korean leader Kim Jong Un. The government has publicly criticised the film saying in a letter to UN secretary general Ban Ki-Moon that is an "undisguised sponsoring of terrorism, as well as an act of war".