The Wall Street Journal reports that a group of hackers in China were able to break through the U.S Chamber of Commerce security system, and gain access to all of its information.  

Hackers reportedly had access to information about 3 million chamber members — including the nation’s largest corporations — for up to a year before being found out. 

The incident was discovered and quietly shut down in 2010, and is among the boldest breaches between the U.S. and China, the newspaper said. 

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