Data breach at the White House? UPDATE: It's for real and Russian

Developing story, reported at Powerlineblog.

"We have yet to hear from the White House press office in response to our request for a comment on our reader’s report that a major network problem has hit the computers used by staff in the Executive Office of the President. Our source, however, updated us with the latest on the issue overnight. He believes it is expected that news of the problem (whatever it is) will soon break publicly, if not today. Describing the problem as a “major data loss,” he believes that repair is expected to take weeks.   From what he understands, this is a serious problem. He asserts: “We are potentially talking OMB, USTR, ONDCP, OPM, and the White House itself(!). Top-line executive deliberations. Gone. Stolen? No idea.”

An update: Limited acknowledgment.  Perhaps only "non-secure" areas were breached.
Major update at the Washington Post:  The White House acknowledges the event which was detected two weeks ago and traced to Russia.  An ally (Britain) alerted Washington to the problem in the "non-secure" part of the President's office network.   Further comment at Powerlineblog emphasizing that the entire network of reporters kept silent for two weeks and somehow it had to be a foreign ally to tell us what was happening under our own noses.