Former top cybersecurity official on why U.S. intelligence missed Russia's SolarWinds hack
American intelligence agencies are still trying to understand and stop the most sophisticated cybersecurity breach in U.S. history. Former Director of the Cybersecurity and Infrastructure Security Agency Chris Krebs, who served under President Trump, joined "CBS This Morning" to discuss the implications of the SolarWinds hack, and why U.S. intelligence missed the attack that affected several government agencies.