What is a CTF?

Photo by Pisit Heng on Unsplash

A Capture the Flag (CTF) is a computer security competition. CTF contests are usually designed to serve as an educational exercise to give participants experience in securing a machine, as well as conducting and reacting to the sort of attacks found in the real world.

Usually are structured in different levels, and each level has a "flag" to capture (i.e. user's password, file with special permissions, etc).