Chinese Hackers Crack Chamber of Commerce Emails stolen in 'very sophisticated' attack By Mark Russell, Newser Staff Posted Dec 21, 2011 3:53 AM CST 11 comments Comments The US Chamber of Commerce was hit last year by a group of hackers from China in a sophisticate attack the compromised the Chamber's entire system. (Shutterstock) (Newser) – In what's generally viewed as the most brazen Chinese cyber attack yet, a group of hackers broke into the US Chamber of Commerce computers, gaining access to the prominent business group's entire system and its database on 3 million members, reports the Wall Street Journal. The infiltration, which was discovered and shut down in May last year, concentrated on four Chamber employees who worked on Asia policy, downloading six weeks of their emails. But the hackers may have had access to the Chamber's network for up to a year. The Chamber only learned of the break-in when it was informed by the FBI, and US officials suspect the hackers are connected to the Chinese government. A Chinese official said that the accusation of government involvement "lacks proof and evidence and is irresponsible." US officials say it is difficult to know just how extensive the security breach was. "What was unusual about it was that this was clearly somebody very sophisticated, who knew exactly who we are and who targeted specific people and used sophisticated tools to try to gather intelligence," said the Chamber's chief operating officer.