hunt-xss

⚠️ AUTHORIZED USE ONLY This skill is for educational purposes or authorized security assessments only. You must have explicit, written permission from the system owner before using this tool. Misuse of this tool is illegal and strictly prohibited.

Mandatory confirmation gate Before running any command that probes, exploits, changes, persists on, extracts data from, or attempts credential access against a target:

1. Ask the user to state the exact target URL, IP, account, or resource.
2. Ask the user to confirm written authorization and the permitted scope.
3. Show the exact command(s) and explain their expected effect.
4. Wait for explicit confirmation in the current conversation.

Without that confirmation, remain read-only and provide defensive guidance only. Prefer a sandbox, disposable VM, or controlled lab.

Autonomous Testing Priority

Verify reflection before claiming XSS — encoding is everything.

Your payload must appear in the response body with angle brackets UNESCAPED. <script> is XSS. <script> is safe encoding — not vulnerable.

Use a UNIQUE NUMERIC CANARY in your proof payload — e.g. <script>alert(91234)</script> or "><img src=x onerror=alert(91234)>. Pick a distinctive 4+ digit number, not alert(1). Practice pages are full of example payloads like alert(1)/alert('XSS') in their hint text; a unique number is how you tell YOUR reflected payload apart from the page's decoy examples. Proof = your alert(<canary>) shows up in the response with raw, unescaped angle brackets.

Try these contexts in order:

1. Inline script injection (works when HTML context allows new tags):

   <script>alert(CANARY)</script>
   

   Use whatever canary string your proof contract specifies. Confirmed when <script>alert(CANARY) appears literally (not HTML-encoded) in the response.

2. Attribute event injection (when < is filtered but attributes are injectable):

   " onmouseover="alert(CANARY)
   " onerror="alert(CANARY)
   " onload="alert(CANARY)
   

3. URL/href context:

   javascript:alert(CANARY)
   

Distinguishing success from failure:

• Vulnerable: response contains <script>alert( unescaped — browser would execute it
• Filtered/safe: response contains <script> or <script> — properly encoded
• Blocked: response is an error, or the reflected value is absent entirely

For stored XSS: inject into a field that other pages display (comments, usernames, ticket titles). Then fetch the rendering page and check for unescaped payload. The payload executes when any user views that page — higher severity than reflected.

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.

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