From the......Background to “Assessing Russian Activities and Intentions in Recent US Elections”: The Analytic Process and Cyber Incident Attribution........report issued by the DNI's office.
Cyber Espionage Against US Political Organizations. Russia’s intelligence services conducted cyber operations against targets associated with the 2016 US presidential election, including targets associated with both major US political parties.
We assess Russian intelligence services collected against the US primary campaigns, think tanks, and lobbying groups they viewed as likely to shape future US policies. In July 2015, Russian intelligence gained access to Democratic National Committee (DNC) networks and maintained that access until at least June 2016.
The General Staff Main Intelligence Directorate (GRU) probably began cyber operations aimed at the US election by March 2016. We assess that the GRU operations resulted in the compromise of the personal e-mail accounts of Democratic Party officials and political figures. By May, the GRU had exfiltrated large volumes of data from the DNC.
Public Disclosures of Russian-Collected Data. We assess with high confidence that the GRU used the Guccifer 2.0 persona, DCLeaks.com, and WikiLeaks to release US victim data obtained in cyber operations publicly and in exclusives to media outlets.
Guccifer 2.0, who claimed to be an independent Romanian hacker, made multiple contradictory statements and false claims about his likely Russian identity throughout the election. Press reporting suggests more than one person claiming to be Guccifer 2.0 interacted with journalists.
Content that we assess was taken from e-mail accounts targeted by the GRU in March 2016 appeared on DCLeaks.com starting in June. We assess with high confidence that the GRU relayed material it acquired from the DNC and senior Democratic officials to WikiLeaks. Moscow most likely chose WikiLeaks because of its self-proclaimed reputation for authenticity. Disclosures through WikiLeaks did not contain any evident forgeries.
Disclaimer: I post this with the full understanding no mountain of evidence is large enough for you to acknowledge your attempts to inject doubt in this matter are in error. I understand you will always maintain a "yeah, but" approach since not admitting Russia was behind the hack is essential to perpetuating right wing media lies about Trump and Russia's efforts to aid his campaign. Lies designed to create doubt, but not offer a counter explanation, where there is no doubt. The fact is Obama was relying on the collective, correct conclusions of the intel community based on the forensic evidence.