Sony executives have declined to comment on the scope of the attack, though emails have been bouncing back with messages asking senders to call employees because the system was "experiencing a disruption." Upcoming Sony films have leaked online today, reportedly as a result of the attack. Representatives with FireEye and the FBI declined comment. Mandiant is an incident response firm that helps victims of breaches identify the extent of attacks, clean up networks and restore systems. The firm has handled some of the largest breaches uncovered to date, including the 2013 holiday attack on Target Corp. Technology news website Re/code reported on that Sony was investigating to determine whether hackers working on behalf of North Korea have launched the attack in retribution for the studio's backing of the film The Interview, which is to be released on December 25 in the United States and Canada.