How to write a good CTF write-up after the event ends

Why write them

Write-ups force you to understand why a solution worked, help other learners, and show employers how you think. A good write-up explains reasoning, not just commands.

A structure that works

Start with the challenge name, category, points, and the description. Summarize the solution in two sentences. Then walk through your approach: first observations, hypotheses, what you tried, what failed and why, and what worked. Include only the relevant commands and output. End with the lesson learned and references.

• Challenge info and description
• Two-sentence summary
• Observations and hypotheses
• Dead ends and why they failed
• Working approach with key commands
• Lesson learned and references

Lab: rewrite one of your notes

Take notes from a challenge you solved on a practice platform that permits write-ups, or from a challenge you built yourself in an earlier lesson. Rewrite them in the structure above in under 800 words. Ask a friend to read it and tell you the one step they did not follow; expand that step.

When and where to publish

Publish only after the event ends and only if the organizers allow it. Some always-on platforms prohibit public write-ups for active content; respect that. A personal blog, a GitHub repository, or CTFtime’s write-up links are common places. Remove any real credentials or personal data that appeared in your notes.