From everything I've read, it sounds like there's reasonable certainty, but that's admittedly anecdotal on my part and comes from mostly secondary sources.
I've read a small selection of the IC reports and declassified info as well that at least support the general tendency of the Kremlin to operate this way as of late.
As an aside, this is a site set up that tracks known Kremlin Internet Research Agency accounts and bots activity:
This area is rather murky. There is a lot of assumptions here. Not even clear these bots are working for Kremlin or for interests of other parties who are hiring them.
I've read a small selection of the IC reports and declassified info as well that at least support the general tendency of the Kremlin to operate this way as of late.
As an aside, this is a site set up that tracks known Kremlin Internet Research Agency accounts and bots activity:
https://dashboard.securingdemocracy.org/
Also it's worth noting that the FBI is currently investigating Russian cash flow into the NRA:
http://www.mcclatchydc.com/news/nation-world/national/articl...