Sony working to remove stolen films from file-sharing sites

The movies include the Brad Pitt war film "Fury," released in the U.S. in October, as well as the upcoming "Annie," "Still Alice," "Mr. Turner" and "To Write Love on Her Arms," according to a source close to the situation, who added that the studio is working to restore its computer systems.

The U.S. film and TV arm of struggling electronics giant Sony came under attack last week from a group that calls itself the Guardians of Peace (GOP). The attack apparently also affected the company's server networks including email.

"The theft of Sony Pictures Entertainment content is a criminal matter, and we are working closely with law enforcement to address it," a Sony spokeswoman said Monday in an email. Sony first said that it was affected by an "IT matter."

The spokeswoman would not confirm news reports that the U.S. Federal Bureau of Investigation is involved in probing the theft, or whether the company hired network security firm FireEye's Mandiant forensics team to help repair damage from the attack.

Other news reports have said North Korea-affiliated hackers may have launched the attack in retaliation for the upcoming Sony film "The Interview," about a plot to assassinate North Korean leader Kim Jong-un. Sony Pictures had no comment when asked who might be responsible for the security breach.

In an email to news media, GOP said it has uploaded Sony Pictures data on the Web. Part of the cache includes information such as sales data for syndicated TV shows as well as some emails and passwords.

"Sony Pictures' recent plan to make another indiscriminate restructuring is the motive of our hack attack," a person claiming to be part of GOP wrote in a separate email, accusing the company of "terrible racial discrimination" and "indiscriminate tyranny."

"We required Sony Pictures to stop this and pay proper monetary compensation to the victims."

Sony Pictures was also hit by a data breach in 2011 in which hacker group LulzSec claimed to have accessed personal data of more than 1 million people.