In an incident that escalated concerns about the potential for Russian meddling in U.S. politics, Reuters first reported on Thursday that the U.S. Federal Bureau of Investigation is probing the hack at the Democratic Congressional Campaign Committee, or DCCC.
The intrusion took place from at least June 19 to June 27, though it may have been longer, according to analysis conducted by U.S. network security company FireEye.
The committee said in a statement it has hired cyber security firm CrowdStrike to investigate. “We have taken and are continuing to take steps to enhance the security of our network,” the committee said. “We are cooperating with federal law enforcement with respect to their ongoing investigation.”
The DCCC hack may be related to an earlier hack against the Democratic National Committee, which raises money and sets strategy for Democratic candidates nationwide. The DNC and DCCC occupy the same office building in Washington.
Potential links to Russian hackers in both incidents were likely to heighten accusations, so far unproven, that Moscow is trying to meddle in the U.S. presidential election campaign to help Republican nominee Donald Trump.
The Kremlin denied involvement in the DNC cyber attack.
In June, a bogus website was registered with a name resembling a DCCC donation site. For some time, donation-related internet traffic that was supposed to go to a donation-processing firm instead went to the fake site.
The DCCC intrusion may have been used to compromise the computer systems of donors who visited the spoof site, rather than to collect their personal information, said John Hultquist, manager of cyber espionage analysis at FireEye.
Several major Democratic donors contacted by Reuters on Friday said they had not been notified of the hack and were not concerned about their information being accessed.
“I’m less concerned about that than I am about my Amex being hacked,” said John Morgan, 60, a Florida attorney.
Cindy Miscikowski, 68, a California donor, said she would be upset if hackers got her bank information, but otherwise she was not worried because donations are disclosed publicly.