Sen. Claire McCaskill,
a Missouri Democrat facing a tough re-election fight, said Thursday that hackers aiming to steal staffers’ passwords failed to infiltrate her Senate office computers, an attempted breach that echoed high-profile thefts during the 2016 presidential campaign.
Earlier Thursday, the Daily Beast website reported that hackers tied to Russia’s GRU intelligence service used a phishing technique to try to trick McCaskill staffers into clicking on malicious web links in order to steal their passwords, citing its own forensic analysis. The involvement of Russian intelligence in the attack couldn’t immediately be independently confirmed.
“Russia continues to engage in cyber warfare against our democracy,” Ms. McCaskill said in a statement. “While this attack was not successful, it is outrageous that they think they can get away with this.”
A similar phishing method was used in the theft of emails from the Democratic National Committee and the
campaign, leading to a series of embarrassing news stories at the height of the race with now-President
U.S. intelligence officials said those break-ins were carried out by Russian intelligence. Earlier this month, special counsel Robert Mueller charged a dozen Russian intelligence officers in the hacks. Russia has denied involvement, and said the indictment was designed to “spoil the atmosphere” of the meeting between Mr. Trump and Russian President
The Russian Embassy in Washington had no immediate comment on the attempted breach of Ms. McCaskill’s computers.
The disclosure of the McCaskill attack comes amid heightened concerns on Capitol Hill and in the national-security community about election interference by Russia. At the Aspen Security Forum in Colorado last week, top U.S. law-enforcement and intelligence officials warned about continued Russian efforts, with Federal Bureau of Investigation Director
asserting that Moscow continues to engage in “malign information operations” in the U.S.
At that same forum, Microsoft vice president
said hackers believed to be tied to Russian intelligence had targeted at least three candidates ahead of the 2018 midterm elections, using faked Microsoft Web domains in attempted phishing attacks. He didn’t disclose the candidates, citing privacy reasons, but said they “might have been interesting targets from an espionage standpoint as well as an election disruption standpoint.” He said the attacks were all unsuccessful and the domains were taken down.
A Microsoft spokeswoman declined to comment on Thursday.
Ms. McCaskill, the top Democrat on the Senate’s Homeland Security and Governmental Affairs Committee, has been outspoken on Russian interference in the election.
“I will continue to speak out and press to hold them accountable,” she said Thursday. “I’ve said it before and I will say it again, Putin is a thug and a bully.”
President Trump plans to meet with his national security staff to discuss election security on Friday afternoon.
Ms. McCaskill is running for re-election in a state Mr. Trump won by almost 20 points. Her seat has become a top target for Republicans in the midterm elections who are hoping to expand their slim 51-49 majority in the Senate. Ms. McCaskill is expected to take on Republican
the state’s attorney general.
Write to Natalie Andrews at Natalie.Andrews@wsj.com