Source?

“We now have high confidence that they hacked the D.N.C. and the R.N.C., and conspicuously released no documents” from the Republican organization, one senior administration official said, referring to the Russians. http://www.nytimes.com/2016/12/09/us/obama-russia-election-h...

The article is very unclear. Here's another quote in the same article that says the hacks against the RNC failed. The NY Times is basically telling us that they received conflicting reports from different anonymous and similarly credible sources.

"One senior government official, who had been briefed on an F.B.I. investigation into the matter, said that while there were attempts to penetrate the Republican committee’s systems, they were not successful."