Another BS Fake News Article. 

If people took the time to follow the links and read thoroughly you can glean they have no evidence other than "high" probability. As it says below CIA "thinks" both the RNC and DNC were attacked. 

The big link:
"We now have high confidence that they hacked the DNC and the RNC, and conspicuously released no documents" from the Republican organization, one senior administration official said, referring to the Russians. For example, intelligence agencies do not have specific intelligence showing officials in the Kremlin "directing" the identified individuals to pass the Democratic emails to WikiLeaks, a second senior U.S. official said. 

What it comes down to is the leader of DNC party, Oboma was playing golf when he should have been working on cyber security. Hey, one senior administration official (me) said, that's a "highly" "probable", "coulda", "guess" of what "kinda" happened.