Kevin Mandia
Founder of Mandiant, the firm that made incident response a brand and named a Chinese military unit in public.
A former US Air Force officer, Mandia founded Mandiant in 2004, and it became the firm you called after the breach. Its 2013 APT1 report tied a long-running espionage campaign to a specific unit of the People's Liberation Army and put the term APT into general circulation.
FireEye bought Mandiant the same year, and Mandia later became its CEO. In December 2020 the company discovered it had itself been breached, and the trail led to the poisoned update of SolarWinds Orion — one of the most extensive supply chain attacks on record. Mandiant was spun out again and acquired by Google in 2022.