A Shanghai-based unit of China's People's Liberation Army has liberated vast amounts of data from the US and other countries in a huge cyber-spying effort over the last seven years, according to a report from computer security firm Mandiant. PLA Unit 61398—known to some victims as the "Comment Crew"—is probably "one of the world's most prolific cyber-espionage groups," according to Mandiant, which has traced thousands of cyberattacks to an area around a 12-story building used by the unit, the BBC reports. Analysts believe the unit employs hundreds, possibly thousands of people fluent in English and skilled in computer programming.
Other security firms—and US intelligence agencies—also believe that the Chinese military is behind the cyberattacks, which have increasingly focused on critical US infrastructure. "Either they are coming from inside Unit 61398," Mandiant's chief executive tells the New York Times, "or the people who run the most-controlled, most-monitored Internet networks in the world are clueless about thousands of people generating attacks from this one neighborhood." White House officials say they are aware of the Mandiant report and plan to warn Beijing that the volume of the attacks threatens to seriously damage US-China relations.