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.
npx agentmods add skills/dailyyarn/ctf-agent/ctf-webnpx skills add dailyyarn/CTF-agent --skill ctf-webgit clone --depth 1 https://github.com/dailyyarn/CTF-agentWrote 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.
[](https://agentmods.dev/skills/dailyyarn/ctf-agent/ctf-web)<a href="https://agentmods.dev/skills/dailyyarn/ctf-agent/ctf-web"><img src="https://agentmods.dev/badge/skills/dailyyarn/ctf-agent/ctf-web.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00100 | $0.07399 |
| Opus 5 | $0.00050 | $0.03700 |
| Sonnet 5 | $0.00020 | $0.01480 |
| Haiku 4.5 | $0.00010 | $0.00740 |
Grade A, and why
ctf-web scanned grade A 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 5d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
- [server-side.md](server-side.md) - Core server-side injection attacks: SQLi (EXIF metadata injection, MySQL column truncation, backslash/hex bypass, second-order, LIKE brute-force, processList trick, XML entity WAF byp Runs shell commandslowCapability
Expected in a hook, worth knowing in a rule or an instructions file.
<%- global.process.mainModule.require('child_process').execSync('id') %> How it starts
The opening of the file, as written. The whole thing — 403 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CTF Web Exploitation
Quick reference for web CTF challenges. Each technique has a one-liner here; see supporting files for full details with payloads and code.
Additional Resources
- server-side.md - Core server-side injection attacks: SQLi (EXIF metadata injection, MySQL column truncation, backslash/hex bypass, second-order, LIKE brute-force, processList trick, XML entity WAF bypass), SSTI (Jinja2, Go, EJS, ERB Sequel bypass, Mako, Twig,
__dict__.update()quote bypass), SSRF (Host header, DNS rebinding, curl redirect), XXE, command injection (newline, blocklist bypass, sendmail, multi-barcode), PHP type juggling, PHP file inclusion / php://filter - server-side-exec.md - Code execution and server-side access attacks: Ruby/Perl/JS code injection, LaTeX injection RCE, PHP preg_replace /e RCE, Prolog injection, ReDoS timing oracle, file upload→RCE (.htaccess, log poisoning, Python .so hijack, Gogs symlink, ZipSlip), PHP deserialization from cookies, PHP extract() variable overwrite, XPath blind injection, Thymeleaf SpEL SSTI + Spring FileCopyUtils WAF bypass, SQLi keyword fragmentation bypass, SQL WHERE ORDER BY bypass, SQL injection via DNS records, API filter injection, WebSocket mass assignment
- server-side-deser.md - Deserialization and execution attacks: Java deserialization (ysoserial gadget chains, JNDI injection, blind detection), Python pickle RCE (
__reduce__, restricted unpickler bypass, STOP opcode chaining), race conditions (TOCTOU async exploits, double-spend, coupon reuse) - server-side-advanced.md - Advanced server-side techniques: ExifTool CVE-2021-22204, Go rune/byte mismatch, zip symlink traversal, path traversal bypasses (brace stripping, double URL encoding, os.path.join, %2f), Flask/Werkzeug debug mode, XXE external DTD filter bypass, WeasyPrint SSRF, MongoDB regex injection, Pongo2 Go template injection, ZIP PHP webshell, basename() bypass, React Server Components Flight RCE (CVE-2025-55182), SSRF→Docker API RCE chain, Castor XML xsi:type deserialization (Atlas HTB), Apache ErrorDocument expression file read (Zero HTB), SQLite file path traversal to bypass string equality
- client-side.md - Client-side attacks: XSS, CSRF, CSPT, cache poisoning, DOM tricks, React input filling, hidden elements, XS-Leak timing oracle, GraphQL CSRF, Unicode case folding XSS bypass (long-s U+017F), CSS font glyph container query exfiltration, Hyperscript CDN CSP bypass, PBKDF2 prefix timing oracle, client-side HMAC bypass via leaked JS secret
- auth-and-access.md - Auth/authz attacks: password inference, weak validation, client-side gates, NoSQL auth bypass, HAProxy/Express.js bypass, IDOR on WIP endpoints, HTTP TRACE method bypass, LLM/AI chatbot jailbreak, open redirect chains (OAuth token theft), subdomain takeover, Apache mod_status info disclosure + session forging
- auth-jwt.md - JWT/JWE token attacks: algorithm none, RS256→HS256 confusion, weak secret, unverified signature, JWK/JKU header injection, KID path traversal, balance replay, JWE forgery with exposed public key
- auth-infra.md - Infrastructure auth: OAuth/OIDC exploitation (redirect_uri bypass, token manipulation, state CSRF), CORS misconfiguration, git history credential leakage, CI/CD variable theft, identity provider API takeover (authentik/Keycloak), SAML SSO flow automation, Guacamole parameter extraction, login page poisoning, TeamCity REST API RCE
- node-and-prototype.md - Node.js: prototype pollution, VM sandbox escape, Happy-DOM chain, flatnest CVE, Lodash+Pug AST injection
- web3.md - Blockchain/Web3: Solidity exploits, proxy patterns, ABI encoding tricks, transient storage clearing collision (0.8.28-0.8.33), Foundry tooling
- cves.md - CVE-specific exploits: Next.js middleware bypass, curl credential leak, Uvicorn CRLF, urllib scheme bypass, ExifTool DjVu, broken auth, AAEncode/JJEncode, protocol multiplexing, React Server Components Flight RCE (CVE-2025-55182), Ruby-SAML XPath digest smuggling (CVE-2024-45409, Barrier HTB), PaperCut NG auth bypass + RCE (CVE-2023-27350, Bamboo HTB), Zabbix blind SQLi (CVE-2024-22120, Watcher HTB)
What ships with it
11 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.
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.
- 5d ago First seen · 403 lines · 100 tokens per session scan A 5f0432c32ff8
ctf-web is a skill published in the GitHub repository dailyyarn/CTF-agent (5 stars, last pushed 5mo ago), licensed MIT. It adds 100 tokens to every session and 7,399 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 2 findings (makes network calls, runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
Other skills, from other repositories
systematic-debugging
Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.
local-ai-agents
Build local-first AI agents that run entirely on a developer workstation with Microsoft Foundry Local and Qwen function-calling models. Covers Small Language Models (SLMs), the OpenAI-compatible local endpoint, sandboxed local tools, local RAG with Chroma, local MCP servers, hybrid cloud/local routing, and the…
next-cache-components-adoption
Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…
next-cache-components-optimizer
Drive a Next.js route to instant navigation by setting up an agentic loop, under Cache Components / PPR, on initial load (hard navigation) and client-side navigation (soft navigation). Encode the goal as a failing @next/playwright instant() e2e and work it to green, one verified route at a time; the shipped test then…
next-partial-prefetching-adoption
Turn on Partial Prefetching in a Next.js app and work through the insights it surfaces. Use when the user wants to enable or adopt Partial Prefetching, flip the partialPrefetching flag, opt routes in with export const prefetch = 'partial', audit Link prefetch={true} behavior, preserve existing prefetched UI with…
chronicle
Analyze Copilot session history for standup reports, usage tips, session search, and session reindexing. Use when the user asks for a standup, daily summary, usage tips, workflow recommendations, wants to search or find past sessions by keyword/file/PR, wants to reindex their session store, or asks about deleting…