PortSwigger - H2C Smuggling Named Top Web Hacking Technique of 2020

In September 2020, Bishop Fox lead researcher Jake Miller pioneered the H2C smuggling hacking technique, demonstrating how upgrading HTTP/1.1 connections to lesser-known HTTP/2 over cleartext (h2c) connections can allow a bypass of reverse proxy access controls, and lead to long-lived, unrestricted HTTP traffic directly to back-end servers. Portswigger named this the top web hacking technique of 2020.