Introduction to CTFs

A CTF (Capture The Flag) is a information security competition that challenges contestants to solve a variety of tasks ranging from exploiting a web page, to decrypting audio steganography, to hacking your way into a server to steal data.

Jeopardy-style CTFs have questions (tasks) in range of categories. For example, these categories may include : forensics, cryptography, binary exploitation, web exploitation, and reverse engineering. Teams can gain points for every solved task. Usually, more points will be given for completing more complicated tasks. In certain CTFs, the next task in a task chain can be opened only after a team solves the previous task.

Tasks are similar to puzzles. Each task has a certain “flag” or solution (usually in the form of a readable message) that teams have to find.

In jeopardy-style CTFs, challenges are divided into four main categories. These are the most common ones :

• Cryptography – involves decrypting a piece of data or file

• Reverse engineering – exploiting a binary file

• Web Exploitation- exploiting web pages

• Pwn – exploiting servers

Here are a couple good resources to start learning material for CTFs!

• http://ctfs.github.io/resources/ – Introduction to common CTF techniques such as cryptography, steganography, web exploits
• https://trailofbits.github.io/ctf/forensics/ – Tips and tricks relating to typical CTF challenges/scenarios
• https://ctftime.org/writeups –Explanations of solutions to past CTF challenges. We also post writeups/tutorials on our website.