A Capture The Flag is a series of puzzles where each one hides a flag, usually a string of text like devsoc{ctf_flag_here}. Solve the puzzle and you get the flag. It’s that simple at the core, even when individual challenges get wild.
What actually happens in a CTF
You get a set of challenges split into categories. Cryptography, web, reverse engineering, binary exploitation, forensics and so on. Each has a point value. You solve it, submit the flag and your team’s score goes up. Most events run for a weekend, and the scoring table updates in real time.
You’re allowed to look things up. Teams share hints. The whole event is built around learning by struggling through a problem with the internet open.
The categories you’ll meet
- Cryptography. Messages scrambled with ciphers and encodings. You work out how it was encoded then decode it. Base64, ROT13, XOR and basic ciphers show up constantly.
- Web. A website with a vulnerability. Maybe a login you can bypass, a hidden parameter or a cookie you can tamper with. You learn to read HTML, inspect requests, and spot mistakes in the code.
- Forensics. You get a file, often an image or a document and the flag is hidden inside it. Hidden files, metadata, steganography, and data packed into weird formats.
- Reverse engineering. You get a compiled program and need to figure out what it does without the source. You poke it, run it, and read its bytes.
- Binary exploitation. The hardest category. You find a bug in a program and turn it into a way to read the flag. Leave this for later.
Tools you’ll want
A browser with developer tools open covers the web category. For the rest, a few free tools carry you a long way:
- CyberChef for decoding and encoding. Paste in something odd and it will usually sort it out.
- strings on the command line prints the readable text hidden inside a file.
- ExifTool reads the metadata buried in images and documents.
- Burp Suite (the free version) or your browser’s network tab for tampering with requests. You can search for free and opensource alts to BurpSuite and extend the capabilities but this requires some form of maturity in the space.
That’s enough for a first event. You don’t need a hacking rig or Kali Linux on the first day.
How to practice as a beginner
There are permanent platforms where challenges are always available.
- picoCTF from CMU, built for beginners, with a great set of warm-up challenges.
- OverTheWire’s Bandit for command line basics that apply everywhere.
- HackTheBox Academy and TryHackMe have structured beginner paths, with free tiers.
Work through picoCTF’s easy challenges first. When one stumps you, read a writeup after you’ve genuinely tried then redo it yourself. The writeup after real effort is where the learning lands.
What a CTF teaches you
Puzzle solving with real tools. You learn to read raw data, inspect what the browser actually sends, and think about how software can be misused. Employers like seeing CTF experience on a resume, and it’s one of the few things you can study where the whole point is breaking things safely.
The skills carry over. Reading a network request properly helps you debug your own app. Understanding ciphers makes you think about how passwords are stored. CTFs essentially make you curious about how things work underneath.
If you want to try your first one with people who’ll point you in the right direction with regards to beginning CTFs, join us on Discord. Bring curiosity. The flag comes with practice.