Boomberg article reveals more details.
In Illinois, investigators found evidence that cyber intruders tried to delete or alter voter data. The hackers accessed software designed to be used by poll workers on Election Day, and in at least one state accessed a campaign finance database. Details of the wave of attacks, in the summer and fall of 2016, were provided by three people with direct knowledge of the U.S. investigation into the matter. In all, the Russian hackers hit systems in a total of 39 states.