What Are CTF Writeups on CTFtime and How Can They Help You Learn?

Updated

CTF writeups on CTFtime are public, post-event solution notes written by players or teams, and they are most useful when you treat them as worked examples rather than answer keys. CTFtime aggregates them in a "New writeups" feed and links them to past events, so you can find how a specific challenge was solved, what tools were used, and where the solver got stuck. They help you learn fastest if you attempt the challenge first, then compare your approach with the writeup.

What a CTF writeup actually contains

A typical writeup walks through one challenge from start to finish:

  • The problem statement — category (web, pwn, crypto, reversing, forensics, misc), points, and any provided files or URLs.
  • Reconnaissance — how the solver inspected the target, e.g. reading source, running file/strings, or checking HTTP responses.
  • The key insight — the vulnerability, weakness, or trick that unlocks the challenge.
  • The exploit or solution — commands, scripts, or payloads, often with the reasoning behind each step.
  • The flag — sometimes included, sometimes redacted.

Because they are written after the event, writeups usually reflect the solver's cleaned-up reasoning, not their real-time confusion. That makes them readable but also means you should not expect every dead end to be documented.

Where writeups live on CTFtime

CTFtime surfaces writeups in a few connected places:

Location What you find there
New writeups The latest published writeups across all events
Past events Each event page links to writeups submitted for that event
Tasks / Writeups Browse by challenge or by event
Team pages Some teams list their own writeups

The site's own description lists "CTF writeups" alongside teams, ratings, and the archive, so writeups are a first-class part of the platform rather than an afterthought.

How to use writeups to actually learn

Reading a writeup passively teaches you very little. A better loop:

  1. Pick a past event from the archive and choose a challenge in a category you want to improve.
  2. Attempt it yourself first — even 20–30 minutes of genuine effort makes the writeup far more instructive.
  3. Read the writeup only after you're stuck or done, and compare: did you miss a tool, a class of bug, or a piece of domain knowledge?
  4. Reproduce the solution on your own machine instead of just reading it.
  5. Note the reusable pattern — e.g. "JWT alg:none bypass," "format string leak to bypass ASLR" — not just the flag.

For example, if you are learning web exploitation, search past events for a web challenge, try it locally, then read two or three writeups for the same challenge. Different solvers often take different routes, and seeing the alternatives is where the real learning happens.

Common pitfalls

  • Spoilers before effort. Reading the writeup first removes the productive struggle that builds skill.
  • Copy-paste without understanding. A working exploit you don't understand won't transfer to the next challenge.
  • Assuming one writeup is complete. Some omit setup, dependencies, or failed attempts; cross-check with another if something doesn't run.
  • Outdated tooling. Older writeups may use tools or versions that have changed, so adapt rather than copy verbatim.

Who benefits most

Writeups are valuable if you are:

  • New to CTFs and want to see how challenges are structured and solved.
  • Preparing for a specific category and want a bank of worked examples.
  • Stuck on a live or past challenge and need a nudge past a single blocker.

They are less useful if you only want final flags, or if you read them without attempting the challenge. Used as a study companion after real effort, CTFtime's writeup feed and event archive are one of the most practical free resources for building CTF skills.