Written by Chris Frates and Curt Devine, CNN

Washington (CNN) -- The North Korean hack of Sony Pictures that unleashed proprietary information, leaked embarrassing emails and brought the multi-billion dollar company's operations to its knees was unprecedented. But cyber security and intelligence experts warn that this is only the beginning.

A CNN review of cyber attacks against federal agencies shows that the number of breaches into government systems is skyrocketing.

"Espionage is happening at a rate we have never seen before," said Denise Zheng, a deputy director at the Center for Strategic and International Studies.

The numbers seem... http://www.cnn.com/2014/12/19/politics/government-hacks-and-security-bre...