unboundcompute/security-agent-skills · skills/testing-postmessage-and-web-message-trust/SKILL.md

testing-postmessage-and-web-message-trust skillA

testing-postmessage-and-web-message-trust is agent-read markdown (skill) from unboundcompute/security-agent-skills: Test cross-document messaging trust, where a browser message handler acts on data whose origin or content an attacker can influence by opening or framing the window, or where code sends sensitive data to another window with a wildcard target. Use when reviewing client code that registers a message event listener and routes the data into the DOM, an evaluation, navigation, or storage, or that posts secrets across windows. Covers a missing, wildcard, or substring origin check, a missing source-win.

Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.

How to install

Latest version
mdr add unboundcompute/security-agent-skills/testing-postmessage-and-web-message-trust@git:20260903.6dac719
Exact content
mdr add unboundcompute/security-agent-skills/testing-postmessage-and-web-message-trust@sha256:53eb7e68b662eff3

Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.

Badge

mdr badge

[![mdr](https://markdownregistry.com/badge/art_trjd45gus56ne3lw.svg)](https://markdownregistry.com/a/art_trjd45gus56ne3lw)

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Versions

versioncommittedcommitsizeaudit
git:20260903.6dac719 latest2026-09-03 6dac719 9,937 BA view

Audit of the latest version

A  17 of 17 checks passed. Deterministic, no model, same answer every run.
  • pass: Frontmatter block present
  • pass: Frontmatter declares a name
  • pass: Frontmatter declares a description
  • pass: Size between 200 bytes and 200 KB (9937 bytes)
  • pass: No zero-width or bidi control characters
  • pass: No instruction hidden inside an HTML comment
  • pass: No link to an exfiltration or paste host
  • pass: No credential-shaped string
  • pass: No instruction to send local credentials anywhere
  • pass: No text hidden with inline styles
  • pass: No prompt-injection phrasing
  • pass: No curl or wget piped into a shell
  • pass: No recursive delete of root, home or parent
  • pass: No instruction to read or print local credentials
  • pass: No base64 blob over 200 characters
  • pass: No link to a raw IP address
  • pass: No script tag

Source

GitHub

unboundcompute/security-agent-skills · 5 stars · license MIT · pushed 2026-09-08 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_trjd45gus56ne3lw
GET https://markdownregistry.com/api/v1/resolve?ref=unboundcompute/security-agent-skills/testing-postmessage-and-web-message-trust
GET https://markdownregistry.com/api/v1/blob/53eb7e68b662eff3e82b487f67503d5f5dc729309e4ab7a54e5950c99a73090e

Agents talk at modelranch.com: hand yours the instructions there and it joins the network that reads files like this one.