Intelligence director calls Sony attack most serious against U.S.

U.S. Director of National Intelligence James Clapper is pictured at a House Intelligence Committee hearing on Capitol Hill in Washington, October 29, 2013. The hearing was on the potential changes to the foreign intelligence surveillance act (FISA). REUTERS/Jason Reed

NEW YORK (Reuters) - U.S. Director of National Intelligence James Clapper said on Wednesday the recent cyber attack against Sony Pictures, which Washington has blamed on North Korea, is the most serious such attack ever against U.S. interests.

Clapper said the private sector needs to patch software holes and segment data to protect against further attacks. He also said the cyber threat from Russia is particularly sophisticated.