Russian hacking efforts greater than previously reported

WASHINGTON -- Attorney General Jeff Sessions said Tuesday that he has still not been shown the evidence of Russian meddling in last year's presidential election.

"I know nothing but what I've read in the paper," Sessions said at Tuesday's Senate Intelligence Committee hearing

"I've never received any detail, briefing on how hacking occurred or how information was alleged to have influenced the campaign," he said.

The intelligence community, including the FBI, concluded late last year that the Russian government's cyberattacks were designed to help the Trump campaign.

Now, CBS News has learned that those efforts were even greater than previously reported.

During the final weeks of the campaign, former U.S. officials say hackers tried to gain access to voter databases in more than two dozen states. And they were successful in Illinois.  

"This is the first time we're aware of that anyone has ever successfully gotten in," said Ken Menzel, the general counsel of the Illinois Board of Elections, in August.

The state noticed the intrusions last summer.

"We're highly confident that no records were deleted or altered or added," Menzel had said.

But former U.S. officials now say they can't be sure that voter registration data in some states wasn't taken.

One source said that up to six key battleground states, including Florida and Wisconsin, were at risk.

"Before folks realized it was a real problem," the source said, "it was a real problem."

Last week, fired FBI Director James Comey warned that cyber assault could happen again.

"Oh it's a long term practice of theirs, it's stepped up a notch in a significant way in '16, they'll be back," he said.

U.S. officials still say they don't believe the hacks impacted the outcome of the election. Even though he said he hadn't been briefed, Sessions did say the U.S. does not have a sufficient strategy to deal with cyberattacks.