How to Prepare for Capture the Flag competitions


Unlike most technical certifications, CTF competitions are 100 percent practical. There’s no multiple choice. To be successful, you’ve got to build up a strong knowledge base, and then draw from it. Though that sounds daunting, it’s not that bad. Provided you’ve learned (or starting learning) white hat basics, you’ll learn everything else you need from practice, practice, and more practice.

There are some great resources with challenging problem sets available for free.


Plenty of aspiring white hats start with PictoCTF. It’s actually intended for middle and high schoolers. For that reason, it covers the basics very well, provides many hints, and reveals challenges as an interesting storyline. If you’re an adult, you can’t compete for prizes, but the lessons are still excellent.

Smash the Stack

Among the most popular wargame sites, Smash the Stack hosts several wargames to attack operating systems, networks, and applications. Most wargames are always online, but they also have regular competitions. Due to its popularity, beginners can reference plenty of write-ups on GitHub, personal blogs, or even YouTube.

Over the Wire

Developed by a robust community of “good-looking hackers,” OverTheWire has wargames for every skill level. The 34-level Bandit wargame is the perfect starting place for absolute beginners. Eventually, you can progress to the Manpage wargame. With each game on its own SSH port, even connecting to the individual games is a learning exercise.


It’s not a pretty website, but Microcorruption shows you how to exploit real-world software flaws with a debugger. Even better, you channel your inner Mission Impossible with a storyline that involves stealing a briefcase of bearer bonds. As they put it, “Should be a milk run. Good luck.”

Google CTF

The Google CTF comprises 23 challenges, and one “Beginners Quest.” The challenges are available year-round, but the team competition aspect only runs for a weekend in the summer. Google pays out $100 for the best 21 write-ups and $500 for the 11 most creative solutions.

Note: These are merely a few popular examples of CTF challenge sites. They are by no means the only resources out there.