Five Chinese men indicted for stealing thousands of emails and documents from U.S. companies had classic hacker nicknames. Yet one thing made them different: their clock-punching day jobs.

Known by handles including UglyGorilla, WinXYHappy and KandyGoo, they worked from 8 a.m. to 6 p.m. with scheduled two-hour lunch breaks, according to a report by online security company FireEye Inc. Rarely working on weekends, the Shanghai-based team acted more like public servants than the stereotype of basement-dwelling loners working around the clock.

For about eight years, the group hacked into U.S. companies including Alcoa Inc., United States Steel Corp. and Westinghouse Electric Co. to steal "sensitive, internal communications," the Department of Justice alleges. The hackers, all officers in Unit 61398 of the Third Department of the Chinese People's Liberation Army, logged standard Chinese hours, rarely did overtime and almost never worked past midnight, according to FireEye research.