auditing-webhook-authenticity-and-callback-trust SKILL.md skillA
auditing-webhook-authenticity-and-callback-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-webhook-authenticity-and-callback-trust@git:20260821.57dfaf1Pins git:20260821.57dfaf1 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-webhook-authenticity-and-callback-trust/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260821.57dfaf1, committed Aug 21, 2026
- Size
- 10,003 bytes
- Repository stars
- 26
- License
- MIT
Audit both directions of webhook trust: an inbound handler that acts on a payload without proving it authentic, and an outbound fetch of a caller-supplied URL that reaches internal targets. Covers inbound handlers with no signature check, a signature compared in non-constant time, a signature computed over a re-serialized body instead of the exact raw bytes, a verification result that is computed but never enforced, and no timestamp or replay defense; and outbound callback or fetch URLs…
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 webhook authenticity and callback trust: proving the caller and pinning the target A webhook is a trust boundary in two directions and both are easy to get wrong. Inbound, an internet caller posts a payload and the handler acts on it, provisioning access or crediting a balance, as if it came from the real sender; the only thing separating the real sender from anyone is a signature check that is often absent, compared unsafely, computed over the wrong bytes, or thrown away. Outbound, the same systems fetch a URL the caller supplied, a callback target or an import link, and a server-side request to an internal address reaches things the internet cannot. You find both by tracing the inbound request to the action it drives and the caller-supplied URL to the request it makes, and asking what proof or restriction stands between. ## When to use - A handler receives a webhook or callback and performs a state change based on its payload. - The application fetches a URL that a user registered or supplied, for a callback, import, preview, or discovery. - You want to know whether an unauthenticated caller can forge an event or steer a server-side request inward. ## Scope check …
Read the whole file at its exact version.
How to install
mdr add unboundcompute/security-agent-skills/auditing-webhook-authenticity-and-callback-trust@sha256:2ea27fb5cabddf79The line at the top of this page pins the label git:20260821.57dfaf1, 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_kpu4dbxmyrukqkmu)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Aug 21, 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 (10003 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_kpu4dbxmyrukqkmu GET https://markdownregistry.com/api/v1/resolve?ref=unboundcompute/security-agent-skills/auditing-webhook-authenticity-and-callback-trust GET https://markdownregistry.com/api/v1/blob/2ea27fb5cabddf798ac3d2ca9de8b0180278e1dbd02339ee49ef75a4bca89909
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.