The Russians ate my homework
"The clumsy snoop broke regulations by taking the classified code, documentation and other materials home to work on using his personal computer, which was running Kaspersky's antivirus, sources told the Wall Street Journal".
Given the known reliability of the WSJ and its anonymous "sources", we can be quite sure that all this is entirely true.
What it shows, I suppose, is that the NSA is utterly incompetent and shouldn't be entrusted with the security of a whelk stall.
And I am always mildly surprised when I am told that people who proved so incompetent that they couldn't prevent their software from being hacked nevertheless are clever enough to know exactly who did the hacking.