FireEye's Mandiant forensics unit's initial investigation revealed that the massive cyber attack that hit Sony Pictures last November was "unparalleled and well-planned."
The Tokyo-based film company has hired the forensics unit to investigate the late November attack.
According to an email obtained by Variety on Sunday, Mandiant CEO Kevin Mandia replied to Sony Entertainment CEO Michael Lynton, stating that the company was attacked by an "organized group." Lynton shared the email with the Sony employees.
"The scope of this attack differs from any we have responded to in the past, as its purpose was to both destroy property and release confidential information to the public," Mandia wrote in the email.
"The bottom line is that this was an unparalleled and well-planned crime, carried out by an organized group, for which neither SPE nor other companies could have been fully prepared."
In another report, the North Korean government denied allegations that it is behind the hack against Sony Pictures, but considered it a "righteous deed of the supporters and sympathizers." North Korea became the primary suspect because the hacking code was similar to the one North Korean hackers used to attack South Korea last year.
Some Sony employees have said they've recently received threatening emails from the head of the "Guardians of Peace," ordering them to sign their names; otherwise their families will be in danger. The Guardians of Peace claimed responsibility for the attack, although another group called DarkSeoul is also being investigated.
Sony has reached out to law enforcement agencies, including the U.S. Federal Bureau of Investigation (FBI), asking for help in the investigation, according to Beta Wired.
Daniel Clemens, chief executive of cyber security firm PacketNinjas, commented that Sony is partly to blame for the massive security breach.
"There are many things Sony could have done to prepare and defend against this attack," he told Reuters.
