Between January 2015 and May 2016, hackers using the pseudonym “Guccifer 2.0” penetrated Democratic National Committee systems and stole 19,252 emails and 8,034 attachments from seven senior staff members. DCLeaks published material in June and July 2016, while WikiLeaks released the main cache on July 22, 2016—days before the Democratic National Convention—and another 8,263 emails on November 6. The disclosures exposed donor information, including credit-card and Social Security numbers, private media contacts, and internal efforts to undermine Bernie Sanders while favoring Hillary Clinton. They also disrupted Clinton’s campaign communications after personal contact information was published.
The leak triggered the July 24, 2016 resignation of DNC chair Debbie Wasserman Schultz, followed by the departures of CEO Amy Dacey, CFO Brad Marshall, and communications director Luis Miranda. On October 7, 2016, the Department of Homeland Security and the Office of the Director of National Intelligence said with confidence that the Russian government directed the breaches and releases to interfere with the election. On July 13, 2018, Special Counsel Robert Mueller indicted 12 Russian military-intelligence officers, alleging they operated Guccifer 2.0 and Fancy Bear. WikiLeaks founder Julian Assange denied the source was a state actor, and Russia denied involvement; those claims conflict with U.S. intelligence findings and cybersecurity analyses from CrowdStrike, Mandiant, SecureWorks, Fidelis, and ThreatConnect.
