The SolarWinds attackers were masters in novel hacking techniques. The White House has said Russian intelligence was behind the hack. Russia has denied any involvement.

SolarWinds Corp. headquarters in Austin, Texas on Tuesday, Dec. 22, 2020. A former security adviser at the IT monitoring and network management company SolarWinds Corp. said he warned management of cybersecurity risks and laid out a plan to improve it that was ultimately ignored. Photographer: Bronte Wittpenn/Bloomberg via Getty Images