auditing-browser-extension-trust SKILL.md skillA
auditing-browser-extension-trust from unboundcompute/security-agent-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add unboundcompute/security-agent-skills/auditing-browser-extension-trust@git:20260825.70f8609Pins git:20260825.70f8609 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- unboundcompute/security-agent-skills
- Path
skills/auditing-browser-extension-trust/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260825.70f8609, committed Aug 25, 2026
- Size
- 9,944 bytes
- Repository stars
- 26
- License
- MIT
Audit a browser extension (Manifest V3) for a trust boundary another web page or extension can cross to reach a privileged capability, after the permission scope and the message-sender checks are resolved. Covers an externally_connectable or onMessageExternal handler that verifies an origin but not the calling script, a content-script-to-background message handler with no sender validation, host permissions broader than the extension needs, a web_accessible_resources page that acts on URL…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Auditing browser extension trust: what another page can reach through the extension A browser extension is dangerous where a web page it does not trust, or another installed extension, can drive one of its privileged capabilities: a host-scoped fetch that carries the user's cookies, a `chrome`-namespace API, or a DOM write in a content script that runs with the extension's reach. The bug is almost always a message boundary that verifies too little: an external handler that checks the calling domain but not that a trusted script is calling, or a content-script-to-background channel that trusts any sender. You audit it by resolving, per privileged sink, whether every path that reaches it validates the sender identity and origin and whether the permission it uses is scoped to what the extension needs. Stay on the extension's trust boundary; the web-page DOM sink taxonomy belongs to the client-side DOM skill. ## When to use - You are reviewing a browser-extension manifest, its background service worker, and its content scripts. - The extension exposes an external message handler, a cross-context channel, or web-accessible resources. …
Read the whole file at its exact version.
How to install
mdr add unboundcompute/security-agent-skills/auditing-browser-extension-trust@sha256:835978bed1b3124dThe line at the top of this page pins the label git:20260825.70f8609, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_7tdjghhqn7okl3ni)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Aug 25, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (9944 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
unboundcompute/security-agent-skills · 26 stars · license MIT · pushed 2026-09-08 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_7tdjghhqn7okl3ni GET https://markdownregistry.com/api/v1/resolve?ref=unboundcompute/security-agent-skills/auditing-browser-extension-trust GET https://markdownregistry.com/api/v1/blob/835978bed1b3124d03a0804c6192829d342815bbfc6dcfacfd2e31e76dc96bc1
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.