Russian hackers have successfully penetrated servers of the Ukrainian gas company at the center of President Donald Trump’s impeachment, the New York Times reported late Monday. Cybersecurity officials told the Times that Russian military hackers have breached Burisma in a campaign that started in November, as impeachment hearings were in full swing. Burisma is the company where former Vice President Joe Biden’s son, Hunter, was a board member, and experts said the timing and target indicate the Russians may be trying to find potentially embarrassing material against the Bidens, the Times said. The attack reportedly bears striking similarities to the 2016 Russian hack into the Democratic National Committee and Hillary Clinton’s campaign chairman. The Burisma hack was carried out by members of Russia’s GRU, a military intelligence unit, the Times reported, who used phishing emails to gain access through Burisma subsidiaries. It it not clear what exactly the hackers might have been searching for, or what they discovered, the Times said.