Foreign hackers target state election systems; FBI investigates

Federal investigators believe hackers based outside of the United States are behind a pair of cyberattacks reported over the summer against election systems in two states, according to an FBI flash alert obtained by Yahoo! News.

The alert, dated Aug. 18, warned officials about attacks in July and August in which hackers "exfiltrated" information from two unidentified state boards of election. Authorities did not say what information was stolen in the attacks, however, unidentified sources told Yahoo! News authorities were referencing separate attacks in Arizona and Illinois.

The Arizona Secretary of State's Office closed part of its voter registration system after the FBI detected "a potential threat" in June and malicious software was found on a computer used to access the system, according to The Arizona Republic. No data was stolen in that attack, a state official told Yahoo! News.

Hackers were, however,  able to steal the personal data of as many as 200,000 Illinois voters during an attack in late July that crippled the state's voter registration system for more than one week, Yahoo! News reported.

"The FBI is requesting that states contact their Board of Elections and determine if any similar activity to their logs, both inbound and outbound, has been detected," the FBI flash alert recommended. "Attempts should not be made to touch or ping the IP addresses directly."

The alert was sent out amid increased fears of foreign cyberattacks after emails from the Democratic National Committee were hacked and as Republican presidential nominee Donald Trump claims the presidential election is rigged.