Cyberwarfare has been in Russias tool box for a while. It has already been used against Ukraine and no doubt it will be used again. I do believe that as a result of sanctions cyber attacks could follow. Although it is unlikely that it would be seriously targeted against the US. Some government pages could get taken down temporarily, but a serious and impactful attack against US would be too costly and achieve too little. The difference here is that a small-scale attack could easily be denied. A cordinated attack would just risk bringing US more strongly into the conflict where Russia does not want the US to be in the first place.