Personal information about tens of thousands of FBI and Homeland Security employees appears to have been compromised. This report from The Telegraph relates some details:
[The hacker] managed to download the details of about 30,000 US government employees from the FBI and Homeland Security, as well as 200GB of data. The data includes more sensitive information like credit card numbers and military emails, he said.
How did he do it? The Telegraph reports that the method was spearphishing. Again.