Sony Pictures Entertainment has released new information about a high-profile cyber attack which exposed unreleased films and personal employee information. Security firm Mandiant, hired to help contain the incident, told Sony that the malware used in the attack was "unprecedented in nature" and "undetectable by industry standard antivirus software." The release of those comments (from an internal memo) appears to be an attempt by Sony to mitigate criticism of its internet security protocols. Mandiant went on to say that the hack's "purpose was to both destroy property and release confidential info," adding that the FBI released a flash alert to warn other organizations of the danger. North Korean hackers are rumored to be behind the attack, though the rogue state recently denied it while calling it "righteous" at the same time.