https://techcrunch.com/2018/07/27/sen-claire-mccaskill-russia-midterm-hacking-daily-beast/

A Democratic senator seeking reelection this fall appears to be the first identifiable target of Russian hacking in the 2018 midterm race. In a new story on the Daily Beast, Andrew Desiderio and Kevin Poulsen reported that Democratic Missouri Senator Claire McCaskill was targeted in a campaign-related phishing attack. That clears up one unspecified target from last week’s statement by Microsoft’s Tom Burt that three midterm election candidates had been targeted by Russian phishing campaigns.

The report cites its own forensic research in determining the attacker is likely Fancy Bear, a hacking group believed to be affiliated with Russian military intelligence.