Russia, China 'aggressively' identifying US operatives

China and Russia are aggressively using stolen data to identify members of the U.S. intelligence community, according to a top security official.

They have been looking at a range of data to determine "who is an intelligence officer, who travels where, when, who's got financial difficulties, who's got medical issues, [to] put together a common picture," William Evanina said in comments to the Los Angeles Times on Monday. Evanina is director of the National Counterintelligence and Security Center.

Evanina also said foreign intelligence services had "absolutely" already used the data against American operatives. However, the nature of that usage is classified. Just one network of U.S. engineers and scientists who provide assistance to undercover operatives has been identified as compromised, he said.

The security of personal information has been at risk since the U.S. Office of Personnel Management had its systems breached earlier this year. Hackers with apparent ties to China exfiltrated OPM files containing information on more than 22 million applicants who had sought security clearances with the U.S. government dating back fifteen years or more. Russian hackers linked to the Kremlin breached an unclassified e-mail server belonging to the Joint Chiefs of Staff in July.