ctf-misc

ctf-misc is a skill for Claude Code from dailyyarn/CTF-agent. It costs 84 tokens per session (5,016 once invoked), scanned C, a copy of ctf-misc, MIT.

A reference guide for miscellaneous capture-the-flag security challenges. It covers puzzles involving encodings, QR codes, radio signals, restricted programs, virtual machines, Kubernetes permissions, and constraint solving.

In plain words
What is it for?
Use it for encoding and steganography puzzles, QR and audio tasks, radio-signal analysis, Python or shell restrictions, WebAssembly games, Kubernetes access-control challenges, Z3 problems, and related CTF tasks.
Why use it?
It gives concise starting points for unusual challenge formats that do not fit common web, cryptography, or reverse-engineering categories.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: positional $N argument; mentions Claude Code.

Good fit Use it for encoding and steganography puzzles, QR and audio tasks, radio-signal analysis, Python or shell restrictions, WebAssembly games, Kubernetes access-control challenges, Z3 problems, and related CTF tasks.

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Install with agentmods
npx agentmods add skills/dailyyarn/ctf-agent/ctf-misc
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add dailyyarn/CTF-agent --skill ctf-misc
Clone the repo
git clone --depth 1 https://github.com/dailyyarn/CTF-agent

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for ctf-misc

README.md
[![agentmods](https://agentmods.dev/badge/skills/dailyyarn/ctf-agent/ctf-misc/github.svg)](https://agentmods.dev/skills/dailyyarn/ctf-agent/ctf-misc)
Your own site
<a href="https://agentmods.dev/skills/dailyyarn/ctf-agent/ctf-misc"><img src="https://agentmods.dev/badge/skills/dailyyarn/ctf-agent/ctf-misc/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for ctf-misc

Your own site · 80×15
<a href="https://agentmods.dev/skills/dailyyarn/ctf-agent/ctf-misc"><img src="https://agentmods.dev/badge/skills/dailyyarn/ctf-agent/ctf-misc.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 84 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,016 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 92% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00084 $0.05016
Opus 5.5 $0.00034 $0.02006
Sonnet 5.5 $0.00017 $0.01003
Haiku 4.5 $0.00008 $0.00502

Measured 1mo ago against content hash ab1fe5e208da, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade C, and why

ctf-misc scanned grade C with 2 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Harvests environment variableshighData exfiltration

Enumerating or grepping the environment for keys collects credentials unrelated to what the mod says it does.

`COPY (SELECT '') TO PROGRAM 'cmd'` executes OS commands as postgres. `pg_read_file('/path')` reads files. Extract credentials from `pg_basebackup` archives (`global/1260` = `pg_authid`). SSH tunnel to Unix sockets: `ssh

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

import urllib.parse
Origin

This is a copy

92% identical to ctf-misc — 138 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

ctf_agent/knowledge/embedded_ctf_skills/ctf-misc/SKILL.md · 401 lines

How it starts

The opening of the file, as written. The whole thing — 401 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CTF Miscellaneous

Quick reference for miscellaneous CTF challenges. Each technique has a one-liner here; see supporting files for full details.

Additional Resources

  • pyjails.md - Python jail/sandbox escape techniques, quine context detection, restricted character repunit decomposition, func_globals module chain traversal, restricted charset number generation, class attribute persistence
  • bashjails.md - Bash jail/restricted shell escape techniques
  • encodings.md - Encodings, QR codes, esolangs, Verilog/HDL, UTF-16 tricks, BCD encoding, multi-layer auto-decoding, Gray code cyclic encoding, indexed directory QR reassembly, multi-stage URL encoding chains, RTF custom tag extraction, SMS PDU decoding
  • rf-sdr.md - RF/SDR/IQ signal processing (QAM-16, carrier recovery, timing sync)
  • dns.md - DNS exploitation (ECS spoofing, NSEC walking, IXFR, rebinding, tunneling)
  • games-and-vms.md - WASM patching, Roblox place file reversing, PyInstaller, marshal (including code injection), Python env RCE, Z3, K8s RBAC, floating-point precision exploitation, multi-phase crypto games with HMAC commitment-reveal and GF(256) Nim, custom assembly language sandbox escape via Python MRO chain, Benford's Law bypass
  • games-and-vms-2.md - ML weight perturbation negation, cookie checkpoint game brute-forcing, Flask cookie game state leakage, WebSocket game manipulation, server time-only validation bypass, LoRA adapter weight merging and visualization, De Bruijn sequence, Brainfuck instrumentation, WASM linear memory manipulation, neural network encoder collision
  • linux-privesc.md - Sudo wildcard parameter injection (fnmatch), crafted pcap for sudoers.d, monit confcheck process injection, Apache -d override, backup cronjob SUID, PostgreSQL COPY TO PROGRAM RCE, PostgreSQL backup credential extraction, NFS share exploitation, SSH Unix socket tunneling, PaperCut Print Deploy privesc, Squid proxy pivoting, Zabbix admin password reset via MySQL, WinSSHTerm credential decryption

Read the full file on GitHub · 401 lines

Files

What ships with it

8 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 1mo ago First seen · 401 lines · 84 tokens per session scan C ab1fe5e208da

Subscribe to this mod's changes

ctf-misc is a skill published in the GitHub repository dailyyarn/CTF-agent (7 stars, last pushed 6mo ago), licensed MIT. It adds 84 tokens to every session and 5,016 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it C with 2 findings (harvests environment variables, makes network calls). It is 92% identical to ctf-misc, differing in 138 lines, and is treated as a copy.

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