Also see Intelligence Contractor Is Charged in First Leak Case Under Trump (NYT)
"This NSA summary judgment is sharply at odds with Russian President Vladimir Putin’s denial last week that Russia had interfered in foreign elections: “We never engaged in that on a state level, and have no intention of doing so.” Putin, who had previously issued blanket denials that any such Russian meddling occurred, for the first time floated the possibility that freelance Russian hackers with “patriotic leanings” may have been responsible. The NSA report, on the contrary, displays no doubt that the cyber assault was carried out by the GRU.Top-Secret NSA Report Details Russian Hacking Effort Days Before 2016 Election
The NSA analysis does not draw conclusions about whether the interference had any effect on the election’s outcome and concedes that much remains unknown about the extent of the hackers’ accomplishments. However, the report raises the possibility that Russian hacking may have breached at least some elements of the voting system, with disconcertingly uncertain results."