Ctf MiscSAFE

Agent skills for solving CTF challenges - web exploitation, binary pwn, crypto, reverse engineering, forensics, OSINT, and more

The instruction file, verbatim from the audited commit — this is the text the model reads, and the surface the audit's instruction layer examines. Quoted here so you can judge it without cloning anything.

---
name: ctf-misc
description: Provides miscellaneous CTF challenge techniques for problems that do not cleanly fit the main categories. Use for encoding puzzles, pyjails, bash jails, RF/SDR, DNS oddities, unicode tricks, esoteric languages, QR or audio puzzles, constraint solving, game theory, unusual sandbox escapes, and hybrid logic puzzles. Prefer a more specific skill first when the challenge is mainly web, pwn, reverse, forensics, malware, OSINT, or crypto. Treat this as the fallback skill for genuine cross-category or edge-case challenges, not the default starting point.
license: MIT
compatibility: Requires filesystem-based agent (Claude Code or similar) with bash, Python 3, and internet access for tool installation.
allowed-tools: Bash Read Write Edit Glob Grep Task WebFetch WebSearch Skill
metadata:
  user-invocable: "false"
---

# CTF Miscellaneous

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

## Prerequisites

**Python packages (all platforms):**
```bash
pip install "pwntools==4.15.0" "segno==1.6.2" z3-solver Pillow numpy requests dnslib
```

**Linux (apt):**
```bash
apt install libzbar0 qrencode ffmpeg
```

**macOS (Homebrew):**
```bash
brew install ffmpeg qrencode
```

**Manual install:**
- SageMath — Linux: `apt install sagemath`, macOS: `brew install --cask sage`

## Additional Resources

- [pyjails.md](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, f-string config injection via stored eval
- [bashjails.md](bashjails.md) - Bash jail/restricted shell escape techniques, HISTFILE file read trick, bash -v verbose mode, ctypes.sh direct C library calls
- [encodings.md](encodings.md) - Encodings, QR codes, esolangs, UTF-16 tricks, BCD encoding, multi-layer auto-decoding, indexed directory QR reassembly, multi-stage URL encoding chains
- [encodings-advanced.md](encodings-advanced.md) - Verilog/HDL, Gray code cyclic encoding, RTF custom tag extraction, SMS PDU decoding, multi-encoding sequential solvers, UTF-9, pixel binary encoding, hexadecimal Sudoku + QR assembly, TOPKEK, MaxiCode
- [rf-sdr.md](rf-sdr.md) - RF/SDR/IQ signal processing (QAM-16, carrier recovery, timing sync)
- [dns.md](dns.md) - DNS exploitation (ECS spoofing, NSEC walking, IXFR, rebinding, tunneling)
- [games-and-vms.md](games-and-vms.md) - WASM patching, Roblox place file reversing, PyInstaller, marshal analysis, Python env RCE, Z3 (including boolean logic gate network SAT solving), K8s RBAC, floating-point precision exploitation, custom assembly language sandbox escape via Python MRO chain
- [games-and-vms-2.md](games-and-vms-2.md) - Cookie checkpoint game brute-forcing, Flask cookie game state leakage, WebSocket game manipulation, server time-only validation bypass, De Bruijn sequence, Brainfuck instrumentation, WASM linear memory manipulation
- [games-and-vms-3.md](games-and-vms-3.md) - memfd_create packed binaries, multi-phase crypto games with HMAC commitment-reveal and GF(256) Nim, emulator ROM-switching state preservation, Python marshal code injection, Benford's Law bypass, parallel connection oracle relay, nonogram solver pipelines, 100 prisoners problem, C code jail escape via emoji identifiers, BuildKit daemon build secret exploitation, Docker container escape, Levenshtein distance oracle attack, taint analysis bypass via type coercion, shredded document pixel-edge reassembly
- [games-and-vms-4.md](games-and-vms-4.md) - Part 4 (2018-era): XSLT as Turing-complete VM, JavaScript MAX_SAFE_INTEGER successor equality, binary search oracle in comparison-only DSL, blind SQLi via script-engine timeout error, OEIS sequence lookup automation, QR code reassembly from format-string constraints, matrix exponentiation for Fibonacci recurrence, Tribonacci for frog-jump counting, Selenium + Tesseract dynamic CAPTCHA, Brainfuck→Piet multi-layer polyglot, bytebeat synth code recognition
- [linux-privesc.md](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
- [ctfd-navigation.md](ctfd-navigation.md) - CTFd platform API navigation without browser: detection, token auth, challenge listing, file download, flag submission, scoreboard, hints, notifications, Python client class

---

## When to Pivot

- If the puzzle is actually centered on cryptography or number theory, switch to `/ctf-crypto`.
- If the challenge is a real binary exploit instead of a jail, toy VM, or encoding problem, switch to `/ctf-pwn` or `/ctf-reverse`.
- If the input is mostly files, images, audio, or packet captures that need recovery work first, switch to `/ctf-forensics`.
- For ML/AI techniques (model attacks, adversarial examples, LLM jailbreaking), see `/ctf-ai-ml`.
- If the NodeJS sandbox uses **vm2** (`npm ls vm2`), check for **CVE-2023-37466** via `Promise[@@species]` with `nesting:true` — the exception handler escapes the context; see `ctf-web/js-sandbox` for the full exploit chain. In misc challenges with bundled JS, always run `npm ls vm2` to detect vulnerable vm2 before trying other escapes.

## Quick Start Commands

```bash
# File identification
file mystery_file
xxd mystery_file | head -5
python3 -c "import magic; print(magic.from_file('mystery_file'))"

# Encoding detection
python3 -c "import base64; print(base64.b64decode('<data>'))"
echo '<data>' | base64 -d
echo '<hex>' | xxd -r -p

# QR code
zbarimg qr.png
python3 -c "from pyzbar.pyzbar import decode; from PIL import Image; print(decode(Image.open('qr.png')))"

# Z

SAFEgrade B · trust 89/100 Nothing in the source contradicts what it says it does. Grade A is reserved for packages that have also passed the behavioural sandbox.

What the source does

Filesystem

none-observed

Network

none-observed

Shell

none-observed

Dependencies

pinned

Secrets in source

none-found

Findings (3)

curl -x http://TARGET:3128 http://127.0.0.1:9191/app

curl -x http://TARGET:3128 http://127.0.0.1:8080/

# Flow: send token first, then server reveals state, then send answer

Gates applied: no_behavioural_pass.