Sony Pictures Entertainment is working on restoring its services and getting its online systems up and running again after the company suffered a massive cyber attack a week ago.

The studio is enlisting the services of Mandiant Forensics to help them deal with the issue.

Mandiant is an incident response company that aids victims of data breach by identifying the extent of the attack, cleaning up the networks and restoring the systems. The company is known to have handled some recent high-end breaches, which include the attack on retail company Target during holiday shopping season 2013.

Sony's computer systems went down on Nov. 24 and showed signs of attack as the picture of a red skull and the phrase "Hacked by #GOP" were displayed across the system. GOP, it was learned, stood for Guardians of Peace.

The Federal Bureau of Investigation is also looking into the hacking incident, which affected various server networks, including Sony's email system.

Part of the attack also involved pirating five of the studio's current and future releases, which were later seen circulating unofficially on file-sharing sites. These include the war movie Fury and the musical Annie, which will hit the big screen on Dec. 19. Other movies involved in the piracy attack are Still Alice, Mr. Turner, and To Write Love on Her Arms.

"The theft of Sony Pictures Entertainment content is a criminal matter, and we are working closely with law enforcement to address it," said a spokesperson for Sony.

GOP told news media that it has uploaded several data from Sony Pictures on the web. Part of the compromised data include emails, passwords and sales data for syndicated TV shows.

"Sony Pictures' recent plan to make another indiscriminate restructuring is the motive of our hack attack," said one member of the GOP. The hackers accused Sony of exercising "indiscriminate tyranny" and "terrible racial discrimination."

"We required Sony Pictures to stop this (sic) and pay proper monetary compensation to the victims," the group said.

In 2011, Sony was also the target of a data breach launched by the hacker group LulzSec, which claimed that it had successfully gained access to the personal data of over 1 million people.

Sony is also investigating the involvement of pro-North Korea hackers, which reportedly launched the attack to denounce the studio's upcoming film The Interview. The comedy, which is scheduled for a Dec. 25 release, is described by the Pyongyang government as an "undisguised sponsoring of terrorism, as well as an act of war." The film talks about the plan of the CIA to assassinate Kim Jong-un, the leader of North Korea.