Capture the Flag (CTF)

CTF stands for Capture the Flag. In the Cyber Security world this relates to events where people aim to use ethical hacking and web exploitation skills to find hidden flags. This may involve hacking into a machine to find the "flag" file or having a series of hidden "flags" (often strings) within a solution designed specifically for these events. 

Organisations may run CTFs internally or publicly prior to or alongside bug bounty programs and penetration tests. You can also find applications to practice security testing through a CTF game.