As hackers from China snooped around the computer system of the U.S. Chamber of Commerce last year, many Chamber employees started receiving a dramatic uptick of spam emails.
The messages, which tried to entice recipients to click on malicious links, appeared to be coming from known Chamber employees. But their Yahoo and Hotmail addresses had been hijacked by hackers, according to a former employee, who spoke on condition of anonymity.

"A few people did click on them," the former employee said in an interview with The Huffington Post.