FireEye says about 50 companies, organizations 'genuinely impacted' by hack

FILE PHOTO: The FireEye logo is seen outside the company's offices in Milpitas, California, December 29, 2014. REUTERS/Beck Diefenbach/File Photo

WASHINGTON (Reuters) - A widespread hack of U.S. government networks has "genuinely impacted" about 50 companies or organizations, the head of one of the largest U.S. cybersecurity companies said on Sunday.

"It is probably only around 50 organizations or companies, somewhere in that zone, that is genuinely impacted," FireEye chief executive Kevin Mandia said in a CBS interview.