hunt-xxe

hunt-xxe is a skill for Claude Code, Codex from adriannoes/awesome-agentic-ai. It costs 31 tokens per session (4,623 once invoked), scanned A, original, MIT.

A security-testing guide for finding XML external entity (XXE) flaws, where an XML parser is tricked into reading files or contacting internal services.

In plain words
What is it for?
Use it to test XML endpoints and server-side processing of SVG, office documents, PDFs, SAML messages, feeds, and SOAP services.
Why use it?
It helps expose unsafe XML processing in APIs, uploads, document converters, and sign-in systems.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument.

Good fit Use it to test XML endpoints and server-side processing of SVG, office documents, PDFs, SAML messages, feeds, and SOAP services.

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Install with agentmods
npx agentmods add skills/adriannoes/awesome-agentic-ai/hunt-xxe
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-xxe
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-xxe

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/hunt-xxe"><img src="https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/hunt-xxe.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 31 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,623 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. ✓ AI security review Sonnet 5 · 7 Sept 2026 📄 Read the review
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 $0.00031 $0.04623
Opus 5 $0.00015 $0.02312
Sonnet 5 $0.00006 $0.00925
Haiku 4.5 $0.00003 $0.00462

Measured 8d ago against content hash 53455e42e91d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

hunt-xxe scanned grade A with 0 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 8d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

cursor-claude-codex/skills/bug-hunter/skills/hunt-xxe/SKILL.md · 367 lines

How it starts

The opening of the file, as written. The whole thing — 367 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Crown Jewel Targets

XXE is a critical-severity vulnerability that consistently pays at the top of bug bounty scales ($5,000–$30,000+) due to its direct path to sensitive data exfiltration and SSRF. Highest-value targets:

  • Large enterprise platforms with XML-heavy backend integrations (finance, logistics, ride-sharing APIs)
  • Domains with file-read capability/etc/passwd, /etc/shadow, internal config files, AWS metadata endpoints
  • Subdomains sharing backend infrastructure — one XXE endpoint can pivot to internal services across dozens of domains (as demonstrated by 26+ Uber domains via a single entry point)
  • API gateways accepting XML content types — especially REST APIs that silently accept Content-Type: application/xml
  • File upload features — SVG, DOCX, XLSX, PDF, PPTX parsers on the server side
  • SAML/SSO endpoints — SAML assertions are XML-based and frequently vulnerable
  • Office/document processing services — any feature that converts or processes user-supplied documents

Attack Surface Signals

URL Patterns

/api/v*/xml
/upload
/import
/parse
/convert
/saml/acs
/sso/saml
/feed
/rss
/sitemap
/webdav
/soap/*
/wsdl
/service.asmx
/xmlrpc
/graphql (multipart with XML)

Request/Response Headers

Content-Type: application/xml
Content-Type: text/xml
Content-Type: application/soap+xml
Content-Type: multipart/form-data  ← check file upload fields
Accept: application/xml
X-Content-Type-Options: (absent — good sign of loose parsing)

JavaScript Patterns (source recon)

// Look for in JS bundles
XMLSerializer
DOMParser
parseFromString
new ActiveXObject("Microsoft.XMLDOM")
$.parseXML(
xml2js
libxmljs
lxml

Tech Stack Signals

  • Java stacks: Spring, Struts, JAX-WS — default XML parsers (SAX, DOM) are XXE-vulnerable without explicit hardening
  • PHP: simplexml_load_string(), DOMDocument::loadXML() — vulnerable by default pre-PHP 8
  • Python: lxml, xml.etree (safe by default), xml.sax (unsafe)
  • Ruby: Nokogiri older versions, REXML
  • Node.js: xml2js, libxmljs, fast-xml-parser (older versions)
  • WSDL/SOAP services: Always test — legacy XML parsing virtually guaranteed
  • File parsers: Apache POI (Java), python-docx, LibreOffice integrations

Read the full file on GitHub · 367 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. 8d ago First seen · 367 lines · 31 tokens per session scan E 53455e42e91d

Subscribe to this mod's changes

hunt-xxe is a skill published in the GitHub repository adriannoes/awesome-agentic-ai (57 stars, last pushed 13d ago), licensed MIT. It adds 31 tokens to every session and 4,623 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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