ctf-misc
The ctf-misc skill provides techniques for solving capture-the-flag challenges that fall outside standard categories, including Python and bash sandbox escapes, encoding puzzles with QR codes and esoteric languages, RF/SDR signal processing, DNS exploitation, constraint solving with Z3, game theory problems, and hybrid logic puzzles. Use this skill as a fallback for genuine cross-category or edge-case challenges after determining the challenge is not primarily a web, pwn, reverse engineering, forensics, malware, OSINT, or cryptography problem.
git clone --depth 1 https://github.com/ljagiello/ctf-skills /tmp/ctf-misc && cp -r /tmp/ctf-misc/ctf-misc ~/.claude/skills/ctf-miscSKILL.md
# 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 z3-solver pwntools Pillow numpy requests dnslib
```
**Linux (apt):**
```bash
apt install ffmpeg qrencode
```
**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`.
## 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')))"
# Z3 constraint solving
python3 -c "from z3 import *; x=BitVec('x',32); s=Solver(); s.add(x^0xdead==0xbeef); s.check(); print(s.model())"
# Python jail test
python3 -c "__import__('os').system('id')"
```
## General Tips
- Read all provided files carefully
- Check file metadata, hidden content, encoding
- Power Automate scripts may hide API calls
- Use binary search when guessing multiple answers
## Common Encodings
```bash
# Base64
echo "encoded" | base64 -d
# Base32 (A-Z2-7=)
echo "OBUWG32D..." | base32 -d
# Hex
echo "68656c6c6f" | xxd -r -p
# ROT13
echo "uryyb" | tr 'a-zA-Z' 'n-za-mN-ZA-M'
```
**Identify by charset:**
- Base64: `A-Za-z0-9+/=`
- Base32: `A-Z2-7=` (no lowercase)
- Hex: `0-9a-fA-F`
See [encodings.md](encodings.md) for Caesar brute force, URL encoding, and full details.
## IEEE-754 Float Encoding (Data Hiding)
**Pattern (Floating):** Numbers are float32 values hiding raw bytes.
**Key insight:** A 32-bit float is just 4 bytes interpreted as a number. Reinterpret as raw bytes -> ASCII.
```python
import struct
floats = [1.234e5, -3.456e-7, ...] # Whatever the challenge gives
flag = b''
for f in floats:
flag += struct.pack('>f', f)
print(flag.decode())
```
**Variations:** DoublProvides AI and machine learning techniques for CTF challenges. Use when attacking ML models, crafting adversarial examples, performing model extraction, prompt injection, membership inference, training data poisoning, fine-tuning manipulation, neural network analysis, LoRA adapter exploitation, LLM jailbreaking, or solving AI-related puzzles.
Provides cryptography attack techniques for CTF challenges. Use when attacking encryption, hashing, signatures, ZKP, PRNG, or mathematical crypto problems involving RSA, AES, ECC, lattices, LWE, CVP, number theory, Coppersmith, Pollard, Wiener, padding oracle, GCM, key derivation, or stream/block cipher weaknesses.
Provides digital forensics and signal analysis techniques for CTF challenges. Use when analyzing disk images, memory dumps, event logs, network captures, cryptocurrency transactions, steganography, PDF analysis, Windows registry, Volatility, PCAP, Docker images, coredumps, side-channel power traces, DTMF audio spectrograms, packet timing analysis, CD audio disc images, or recovering deleted files and credentials.
Provides malware analysis and network traffic techniques for CTF challenges. Use when analyzing obfuscated scripts, malicious packages, custom crypto protocols, C2 traffic, PE/.NET binaries, RC4/AES encrypted communications, YARA rules, shellcode analysis, memory forensics for malware (Volatility malfind, process injection detection), anti-analysis techniques (VM/sandbox detection, timing evasion, API hashing, process injection, environment checks), or extracting malware configurations and indicators of compromise.
Provides open source intelligence techniques for CTF challenges. Use when gathering information from public sources, social media, geolocation, DNS records, username enumeration, reverse image search, Google dorking, Wayback Machine, Tor relays, FEC filings, or identifying unknown data like hashes and coordinates.
Provides binary exploitation techniques for CTF challenges. Use when you already have a vulnerable native target or service and need to turn memory corruption or low-level primitives into code execution or privilege escalation, such as buffer overflows, format strings, heap bugs, ROP, ret2libc, shellcode, kernel exploitation, seccomp bypass, sandbox escape, or Windows/Linux exploit chains. Do not use it when the main blocker is understanding what the binary does; use reverse engineering first. Do not use it for pure web bugs, disk or packet forensics, or standalone crypto/math challenges.
Provides reverse engineering techniques for CTF challenges. Use when the main job is to understand how a compiled, obfuscated, packed, or virtualized target works before exploiting or solving it, including binaries, APKs, WASM, firmware, custom VMs, bytecode, game clients, malware-like loaders, and anti-debug or anti-analysis logic. Do not use it when the vulnerability is already understood and the remaining task is exploitation; use pwn instead. Do not use it for pure web workflows, log or disk forensics, or standalone crypto problems unless reversing the implementation is the real blocker.
Provides web exploitation techniques for CTF challenges. Use when the target is primarily an HTTP application, API, browser client, template engine, identity flow, or smart-contract frontend/backend surface, including XSS, SQLi, SSTI, SSRF, XXE, JWT, auth bypass, file upload, request smuggling, OAuth/OIDC, SAML, prototype pollution, and similar web bugs. Do not use it for native binary memory corruption, reverse engineering of standalone executables, disk or memory forensics, or pure cryptanalysis unless the web flaw is still the main path to the flag.