By Brendan Sasso - 02/20/13 03:41 PM EST
Analysts traced a series of attacks to a 12-story building in the Pudong district of Shanghai. They concluded that the building, which likely holds hundreds or even thousands of employees, is almost certainly the headquarters of China's secretive cyber war division, the People's Liberation Army Unit 61398.
Mandiant concluded that since 2006, the Chinese unit has stolen data from at least 141 companies across 20 major industries, including critical infrastructure sectors like energy and telecommunications. At least 115 of the companies were in the United States.
—Updated at 12:28 p.m.