Basically, there's no proof listed at all that the Russian government was behind anything. Is it possible? Sure. But if they are going to make the claim and say it is for sure the Russian government, then why can't they give the proof saying as such?
Link to the JAR: https://www.us-cert.gov/sites/default/f ... 6-1229.pdf
link to Ars Technica report on it: http://arstechnica.com/security/2016/12 ... o-rage-on/
I think its pretty damn irresponsible for our government to make this claim, then have no means to back it up.