Following the Democratic National Committee’s (DNC) announcement of a breach in June 2016, a report by CrowdStrike detailed its findings about the threat actors behind the attack concluding it was the work of two different sophisticated Russian-based APT groups.
Subsequently, an individual called Guccifer 2.0 claimed responsibility for the attack – countering Crowdstrike’s claims that it was a sophisticated breach – and leaked documents to Wikileaks as proof. ArsTechnica reported, “…either CrowdStrike misattributed the breach to the wrong groups or failed to detect that one or more additional actors had also gained high-level access and made off with a trove of confidential information.”
The Crowdstrike report claimed it was the work of adversaries dubbed Fancy Bear and Cozy Bear. Some background on the suspected threat actors:
Fancy Bear
Cozy Bear