The Hacker101 CTF is a game designed to let you learn to hack in a safe, rewarding environment. Hacker101 is a free educational site for hackers, run by HackerOne. This CTF is another integral component in our plans to make the world a better place, one bug at a time.
CTF stands for Capture The Flag, a style of hacking event where you have one goal: hack in and find the flag. Flags are placed in various locations -- they might be in a file, in the database, stuck into source code, or otherwise -- and your goal is to hunt them all down. Each flag looks something like
^FLAG^37ae568362f974017fa575f08cd215044cd6bb395c3f5e5e293ee5324ba6769c$FLAG$, so you'll know the instant you see one.
Whether you're brand new or a seasoned hacker, you may also want to check out our companion site, Hacker101, where you can learn everything from absolute beginner to advanced hacking techniques.