xxe-xml-external-entity

xxe-xml-external-entity is a skill for Claude Code, Codex from jinyimeng01/net-code-audit-skill-master. It costs 0 tokens per session (4,601 once invoked), scanned E, original, MulanPSL-2.0.

A security-audit guide for XML external entity vulnerabilities, which can occur when XML processing loads outside files or network resources.

In plain words
What is it for?
Use it when reviewing .NET features that accept or parse XML.
Why use it?
It helps auditors check whether untrusted XML could expose files or make unwanted network requests.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing.

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.

agentmods
npx agentmods add skills/jinyimeng01/net-code-audit-skill-master/xxe-xml-external-entity
Any agent
npx skills add jinyimeng01/net-code-audit-skill-master --skill xxe-xml-external-entity
Clone the repo
git clone --depth 1 https://github.com/jinyimeng01/net-code-audit-skill-master

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 xxe-xml-external-entity

README.md
[![agentmods](https://agentmods.dev/badge/skills/jinyimeng01/net-code-audit-skill-master/xxe-xml-external-entity.svg)](https://agentmods.dev/skills/jinyimeng01/net-code-audit-skill-master/xxe-xml-external-entity)
Your own site
<a href="https://agentmods.dev/skills/jinyimeng01/net-code-audit-skill-master/xxe-xml-external-entity"><img src="https://agentmods.dev/badge/skills/jinyimeng01/net-code-audit-skill-master/xxe-xml-external-entity.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,601 The whole file, excluding the scripts and references it only reads on demand.
Security scan E 3 findings. Scan, not verified.
Origin unknown 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 $0.00000 $0.04601
Opus 5 $0.00000 $0.02301
Sonnet 5 $0.00000 $0.00920
Haiku 4.5 $0.00000 $0.00460

Measured 6d ago against content hash 221cbc1401e0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade E, and why

xxe-xml-external-entity scanned grade E with 3 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 6d 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.

Hidden instructionshighPrompt injection

Directives inside HTML comments, invisible characters or bidirectional overrides are read by the model and not by the person reviewing the file.

<!-- Decode base64 in response to get file contents -->

Reaches for credential filesmediumPrivilege escalation

SSH keys, cloud credentials, git-credentials, .npmrc, /etc/shadow: reading these is how a config file becomes a credential leak.

/home/USER/.ssh/id_rsa ← SSH private key

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Cloud metadata endpointmediumServer-side request forgery

One request to 169.254.169.254 can return temporary IAM credentials.

<!ENTITY xxe SYSTEM "http://169.254.169.254/latest/meta-data/iam/security-credentials/">

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

net-skill/dotnet-offsec-audit/references/raw/hack-skills/xxe-xml-external-entity/SKILL.md · 561 lines

The source is not reproduced here

Licensed MulanPSL-2.0

The repository is licensed MulanPSL-2.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

Files

What ships with it

1 file 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.

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. 6d ago First seen · 561 lines · 0 tokens per session scan E 221cbc1401e0

Subscribe to this mod's changes

xxe-xml-external-entity is a skill published in the GitHub repository jinyimeng01/net-code-audit-skill-master (5 stars, last pushed 4mo ago), licensed MulanPSL-2.0. It costs nothing until one of its globs matches a file; then it loads 4,601 tokens. A static security scan graded it E with 3 findings (hidden instructions, reaches for credential files, cloud metadata endpoint). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Related

Other skills, from other repositories

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

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…

microsoft/ai-agents-for-beginners · 200 tokens

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…

vercel/next.js · 95 tokens

chat-pet-sprite-creation

Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.

microsoft/vscode · 53 tokens

cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…

microsoft/vscode · 71 tokens

insight-error-page

Write or audit an insight-kind error page for the Next.js dev overlay. Use when creating a new errors/ .mdx page, auditing an existing one, or checking that a page matches the framework fix cards. Covers page structure, title alignment, FixCard cards with Copy prompt button, code snippets, terminology verification…

vercel/next.js · 83 tokens