DHS cybersecurity head: 'No doubt' Russians penetrated voter registration systems

03:07

In an exclusive interview with NBC News' Cynthia McFadden, Jeanette Manfra, the head of cybersecurity at the Department of Homeland Security, says that 21 states were targeted during the 2016 election. CORRECTION: This Nightly News segment has been updated to correct a map of 21 states that officials say were targeted by Russian hackers. Our original report incorrectly showed Georgia and omitted Alaska. Georgia is not one of the 21 targeted states; Alaska is.