CNET

Getting an e-mail from your employer with the subject line "Cyber Incident" usually isn't good news. Especially if you work for the U.S. Department of Energy and it's the second time this year.

The Energy Department on Wednesday notified workers that a hack in late July exposed personal information, such as the names and Social Security numbers of current and past employees, and that 14,000 people may have been affected.

According to the e-mail, obtained by the Wall Street Journal, the agency said "No classified data was targeted or compromised." The department added that it's working with federal law enforcement to find out more about the incident.

A person familiar with the matter told the Journal that hackers were able to gain access to a human resources system that included information like payroll data.

In February, the agency confirmed its computer systems' had been hacked the month before. In that e-mail to employees, the Energy Department said the hack "resulted in the unauthorized disclosure of employee and contractor Personally Identifiable Information." It also said then that "no classified data was compromised."

That incident affected several hundred people, according to the Journal. News of the earlier incident followed a string of hacks targeting The New York Times, the Washington Post, and the Journal as well as companies such as Twitter and, it was later revealed, Facebook and Apple.

The Energy Department did not say in the memo whether it knows who was behind the latest attack. CNET has contacted the department for comment. We'll update the story when we hear back.

Below is a copy of the e-mail obtained by the Journal: