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CTF File Parser Chain

Traces how an uploaded file moves through parsers, converters and extractors in CTF sandbox work

Source Download skill
Repository
zhaoxuya520/reverse-skill
Stars
43,969
Licence
MIT
Files
3 files

What it does

This is a specialist instruction set for an AI agent working on capture-the-flag style security exercises. Once installed, when asked to follow an uploaded or imported file through archive extraction, format conversion, previews and parsers, the agent maps each step in order, keeps original and derived files separate, and reduces the path to the smallest sequence that produces a notable backend effect. It is written as a downstream add-on that only applies after a parent sandbox orchestrator skill has already set the assumptions and routed the task here.

Great for

  • Security students working on CTF challenges involving file uploads or deserialization
  • Penetration testers reviewing how an authorised lab application handles uploaded files

Skip it if

  • Testing live production systems or third-party services without written authorisation, since the skill is aimed at sandboxed competition targets and does not itself check scope
  • Standalone use without the parent ctf-sandbox-orchestrator skill, since the file says it should return to that skill first and the description says it is internal

Try asking

  • “Trace how this uploaded zip archive gets extracted and which parser reads each member in the sandbox challenge”
  • “Explain how this imported document reaches the converter and where the file type decision is made”
  • “Show the minimal upload sequence that leads from the uploaded file to the deserializer in this lab app”
Step-by-step guide: how to use CTF File Parser ChainInstall, first run, examples, tips and FAQs

Install in 3 steps

  1. 1

    Download the skill

    The ZIP contains the 3 original files, the MIT licence and an attribution note.

    competition-file-parser-chain.zip
  2. 2

    Add it to your agent

    Claude Code (all projects)

    mkdir -p ~/.claude/skills && unzip competition-file-parser-chain.zip -d ~/.claude/skills/

    Claude Code / Agent SDK (this project only)

    mkdir -p .claude/skills && unzip competition-file-parser-chain.zip -d .claude/skills/

    Claude apps (web/desktop): Settings → Capabilities → Skills → Upload skill, and choose the ZIP.

  3. 3

    Ask for the task

    No special command needed — the agent reads the skill's description and loads it when your request matches. Try one of the prompts above.

Get better results

  • Install and run the parent ctf-sandbox-orchestrator skill first, otherwise this skill tells the agent to route elsewhere
  • Only point it at sandboxed competition targets you are authorised to test

What's inside

  • agents/openai.yaml
  • references/file-parser-chain.md
  • SKILL.md

Redistributed unmodified from zhaoxuya520/reverse-skill under the MIT licence. The assessment was drafted with AI from the skill's files on 2026-10-29. Skills can instruct your agent to run code — read SKILL.md and any scripts before installing.