hunt-xss

hunt-xss is a skill for Claude Code, Codex from adriannoes/awesome-agentic-ai. It costs 30 tokens per session (4,401 once invoked), scanned C, original, MIT.

A security-testing guide for finding cross-site scripting (XSS), a flaw that lets attacker-controlled code run in another person’s browser.

In plain words
What is it for?
Use it during authorized testing of dashboards, payment flows, shared content, sign-in pages, uploads, and documentation sites.
Why use it?
It helps locate places where unsafe content could steal sessions, affect administrators, or cross user boundaries.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it during authorized testing of dashboards, payment flows, shared content, sign-in pages, uploads, and documentation sites.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/adriannoes/awesome-agentic-ai/hunt-xss
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 adriannoes/awesome-agentic-ai --skill hunt-xss
Clone the repo
git clone --depth 1 https://github.com/adriannoes/awesome-agentic-ai

Made for: Claude Code, Codex.

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 hunt-xss

README.md
[![agentmods](https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/hunt-xss/github.svg)](https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/hunt-xss)
Your own site
<a href="https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/hunt-xss"><img src="https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/hunt-xss/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 hunt-xss

Your own site · 80×15
<a href="https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/hunt-xss"><img src="https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/hunt-xss.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 30 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,401 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 original No closer match found 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 $0.00030 $0.04401
Opus 5 $0.00015 $0.02201
Sonnet 5 $0.00006 $0.00880
Haiku 4.5 $0.00003 $0.00440

Measured 9d ago against content hash 2b8a98d7560b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade C, and why

hunt-xss 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 9d 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.

Encoded or obfuscated payloadhighSupply chain

base64 or hex that is decoded and executed hides what actually runs from anyone reading the file.

<svg onload=eval(atob('YWxlcnQoMSk='))>

Makes network callslowCapability

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

curl -sk "https://target.com/search?q=XSSCANARY" | grep -i "XSSCANARY"
cursor-claude-codex/skills/bug-hunter/skills/hunt-xss/SKILL.md · 336 lines

How it starts

The opening of the file, as written. The whole thing — 336 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Crown Jewel Targets

XSS is high-value when it combines privileged context + persistent delivery + scope escalation. The highest payouts come from:

  • Admin panels and authenticated dashboards (e.g., */admin, */settings) — attacker can hijack sessions with elevated privileges, exfiltrate tokens, or pivot to account takeover
  • Payment/financial flows (paypal.com, checkout pages, currency converters) — XSS here enables credential harvesting and financial fraud at scale
  • Stored XSS in collaborative features (wikis, markdown renderers, issue trackers, RDoc, labels, tags) — one payload infects every viewer, multiplying impact
  • SSO/signin pages (e.g., paypal.com/signin) — XSS here is critical because it can steal auth tokens across the entire platform
  • Shared SaaS tenant surfaces (*.myshopify.com, api.collabs.*) — XSS in one tenant's context can bleed across tenant boundaries
  • Help/documentation sites (help.shopify.com) — lower severity individually, but often have looser sanitization and trusted user perception
  • SVG/file upload endpoints — frequently bypasses CSP and sanitization simultaneously

Asset types that pay most: Main product domains > Admin subdomains > API endpoints > Marketing/help sites


OOB-Or-It-Didn't-Happen Gate (Blind / Stored XSS)

For blind and stored XSS — claims require an out-of-band confirmation, the same as blind SSRF. The OOB receiver fires when the payload actually executes in a browser somewhere (an admin reviewing logs, a SOC analyst opening a ticket, an email rendering a stored payload).

What is NOT confirmation

  • ASP.NET request validator rejected your < and returned a different status code → not XSS, that's WAF noise.
  • Your payload appears in the response body URL-encoded or HTML-encoded → not XSS, that's correct output encoding.
  • The form action attribute contains your payload string as %22onclick%3D… → not XSS, the browser does NOT decode URL encoding inside HTML attribute values; the %22 stays as literal %22 in the DOM.
  • Your <script> tag appears in the response as &lt;script&gt; → not XSS, that's escaping.

Read the full file on GitHub · 336 lines

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. 9d ago First seen · 336 lines · 30 tokens per session scan C 2b8a98d7560b

Subscribe to this mod's changes

hunt-xss is a skill published in the GitHub repository adriannoes/awesome-agentic-ai (57 stars, last pushed 14d ago), licensed MIT. It adds 30 tokens to every session and 4,401 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it C with 2 findings (encoded or obfuscated payload, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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