solve-challenge
The solve-challenge skill performs initial triage on CTF challenges by exploring files, connecting to remote services, and identifying the dominant category (forensics, reverse engineering, pwn, crypto, web, or misc) before routing execution to specialized ctf-* skills. Use it when you receive an ambiguous challenge bundle, suspicious file, or vague description and must determine the correct starting approach; skip it when the challenge category is already clear and a specialized skill can be invoked directly.
git clone --depth 1 https://github.com/ljagiello/ctf-skills /tmp/solve-challenge && cp -r /tmp/solve-challenge/solve-challenge ~/.claude/skills/solve-challengeSKILL.md
# CTF Challenge Solver You're a skilled CTF player. Your goal is to solve the challenge and find the flag. ## Environment Setup Two setup strategies depending on your workflow: ### Pre-install (recommended before competitions) Use the central installer entrypoint: ```bash bash scripts/install_ctf_tools.sh all ``` Run a narrower mode when you only want one tool group: ```bash bash scripts/install_ctf_tools.sh python bash scripts/install_ctf_tools.sh apt bash scripts/install_ctf_tools.sh brew bash scripts/install_ctf_tools.sh gems bash scripts/install_ctf_tools.sh go bash scripts/install_ctf_tools.sh manual ``` The full package lists now live in [scripts/install_ctf_tools.sh](../scripts/install_ctf_tools.sh). ### On-demand (during challenges) Each category skill's `SKILL.md` has a **Prerequisites** section listing only the tools needed for that category. Install as you go. ## Workflow ### Step 0: CTFd Platform Detection If the CTF platform URL is known, check if it runs CTFd and switch to API-driven navigation: ```bash # Detect CTFd (look for /api/v1/ and /themes/core/) curl -s "$CTF_URL/api/v1/" | head -5 curl -s "$CTF_URL" | grep -oE '/themes/core/' ``` If CTFd is detected, **ask the user for their API token** (generated from CTFd Settings > Access Tokens). The token is not provided by default — the user must create one in the CTFd web UI first. Once provided, set the environment variables and proceed via API: ```bash export CTF_URL="https://ctf.example.com" export CTF_TOKEN="ctfd_..." # Ask user for this ``` Invoke `/ctf-misc` and load its `ctfd-navigation.md` for the full API reference and Python client class. ### Step 1: Recon 1. **Explore files** -- List the challenge directory, run `file *` on everything 2. **Triage binaries** -- `strings`, `xxd | head`, `binwalk`, `checksec` on binaries 3. **Fetch links** -- If the challenge mentions URLs, fetch them FIRST for context 4. **Connect** -- Try remote services (`nc`) to understand what they expect 5. **Read hints** -- Challenge descriptions, filenames, and comments often contain clues ### Step 2: Categorize Determine the primary category, then invoke the matching skill. **By file type:** - `.pcap`, `.pcapng`, `.evtx`, `.raw`, `.dd`, `.E01` -> forensics - `.elf`, `.exe`, `.so`, `.dll`, binary with no extension -> reverse or pwn (check if remote service provided -- if yes, likely pwn) - `.py`, `.sage`, `.txt` with numbers -> crypto - `.apk`, `.wasm`, `.pyc` -> reverse - Web URL or source code with HTML/JS/PHP/templates -> web - Images, audio, PDFs with no obvious content -> forensics (steganography) **By challenge description keywords:** - "buffer overflow", "ROP", "shellcode", "libc", "heap" -> pwn - "RSA", "AES", "cipher", "encrypt", "prime", "modulus", "lattice", "LWE", "GCM" -> crypto - "XSS", "SQL", "injection", "cookie", "JWT", "SSRF" -> web - "disk image", "memory dump", "packet capture", "registry", "power trace", "side-channel", "spectrogram", "audio tracks", "MKV" -> forensics - "find", "locate", "identify", "who", "where" -> osint - "obfuscated", "packed", "C2", "malware", "beacon" -> malware - "jail", "sandbox", "escape", "encoding", "signal", "game", "Nim", "commitment", "Gray code" -> misc **By service behavior:** - Port with interactive prompt, crash on long input -> pwn - HTTP service -> web - netcat with math/crypto puzzles -> crypto - netcat with restricted shell or eval -> misc (jail) ### Step 3: Invoke the Category Skill Once you identify the category, **invoke the matching skill** to get specialized techniques: | Category | Invoke | When to Use | |----------|--------|-------------| | Web | `/ctf-web` | XSS, SQLi, SSTI, SSRF, JWT, file uploads, prototype pollution | | Pwn | `/ctf-pwn` | Buffer overflow, format string, heap, ROP, sandbox escape | | Crypto | `/ctf-crypto` | RSA, AES, ECC, PRNG, ZKP, classical ciphers | | Reverse | `/ctf-reverse` | Binary analysis, game clients, VMs, obfuscated code | | Forensics | `/ctf-forensics` | Disk images, memory dumps, event logs, stego, network captures | | OSINT | `/ctf-osint` | Social media, geolocation, DNS, public records | | Malware | `/ctf-malware` | Obfuscated scripts, C2 traffic, PE/.NET analysis | | Misc | `/ctf-misc` | Jails, encodings, RF/SDR, esoteric languages, constraint solving | You can also invoke `/ctf-<category>` to load the full skill instructions with detailed techniques. ### Step 4: Pivot When Stuck If your first approach doesn't work: 1. **Re-examine assumptions** -- Is this really the category you think? A "web" challenge might need crypto for JWT forgery. A "forensics" PCAP might contain a pwn exploit to replay. 2. **Try a different category skill** -- Many challenges span multiple categories. Invoke a second skill for the cross-cutting technique. 3. **Look for what you missed** -- Hidden files, alternate ports, response headers, comments in source, metadata in images. 4. **Simplify** -- If an exploit is too complex, check if there's a simpler path (default creds, known CVE, logic bug). 5. **Check edge cases** -- Off-by-one, race conditions, integer overflow, encoding mismatches. **Common multi-category patterns:** - Forensics + Crypto: encrypted data in PCAP/disk image, need crypto to decrypt - Web + Reverse: WASM or obfuscated JS in web challenge - Web + Crypto: JWT forgery, custom MAC/signature schemes - Reverse + Pwn: reverse the binary first, then exploit the vulnerability - Forensics + OSINT: recover data from dump, then trace it via public sources - Misc + Crypto: jail escape requires building crypto primitives under constraints - OSINT + Stego: social media posts with unicode homoglyph steganography (Cyrillic lookalikes encode bits) - Web + Forensics: paywall bypass (curl reveals content hidden by CSS overlays) - Misc + Crypto + Game Theory: multi-phase interactive challenges with AES decryption → HMAC commitment → combinatorial game solving (GF(256) Nim) - Crypto + Geometry + Lattice: multi-layer challenges prog
Provides 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 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.
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.