He said that the system had recognized the IP addresses that were scanning the system and blocked them.
Ebel on Friday said he wasn't aware that the Secretary of State's Office had been communicating with federal agencies about suspected Russian hacker IP addresses.
The Department of Homeland Security confirmed it had notified the 21 states but declined to identify them Friday.
He says the hackers were unable to find any vulnerability in the state system and "weren't able to get any kind of intrusion into anything".
The government did not say who was behind the hacking attempts or provide details about what had been sought. If the system were compromised, Maine's same-day voter registration law would still ensure that no voter is disenfranchised at the polls.
"It's really reconnaissance by a bad guy to try and figure out how we would break into your computer", said Trevor Timmons, a spokesman for the Colorado secretary of state's office.
Only Illinois reported that hackers had succeeded in breaching its voter systems.
A special counsel is investigating whether there was any coordination during the 2016 presidential campaign between Russian Federation and associates of President Donald Trump.
The Wisconsin Elections Commission could soon decide whether it will respond to a series of election policy questions posed by President Trump's task force that is investigating voter fraud.