auditing-jwt-verification-and-key-trust SKILL.md skillA
auditing-jwt-verification-and-key-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-jwt-verification-and-key-trust@git:20260829.b60f9b2Pins git:20260829.b60f9b2 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-jwt-verification-and-key-trust/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260829.b60f9b2, committed Aug 29, 2026
- Size
- 9,696 bytes
- Repository stars
- 26
- License
- MIT
Audit how a service verifies JSON Web Tokens for the classic verification bypasses: an algorithm-confusion attack where a token switches the signing algorithm so a public key is used as a symmetric secret or the algorithm is set to none, a key selected from an attacker-controllable header (a key id, a JWKS URL, or an embedded key) so the token names its own signer, a signature that is decoded but not actually verified, and claims (expiry, issuer, audience) that are parsed but not enforced.…
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 JWT verification and key trust: the token names its own signer unless you stop it A JSON Web Token is a signed claim, and its security is entirely in how the verifier checks the signature and the claims. The failures are a small, famous set, and they recur because the token itself carries the parameters an attacker wants to control. The algorithm lives in the token header, so a verifier that trusts it can be steered into algorithm confusion, verifying an RS256 token as HS256 using the public key as the shared secret, or accepting an algorithm of none with no signature at all. The key can be selected from the header too, a key id, a JWKS URL, or an embedded key, so a token can name a signer the attacker controls. A verifier that decodes the token and reads the claims but never actually checks the signature accepts anything. And a verifier that checks the signature but not the expiry, issuer, and audience honors expired or wrong-context tokens. The audit pins the algorithm and key on the server side and confirms the signature and claims are enforced. You audit this by presenting manipulated tokens and confirming each is refused. ## When to use …
Read the whole file at its exact version.
How to install
mdr add unboundcompute/security-agent-skills/auditing-jwt-verification-and-key-trust@sha256:8858cbd9eb1343e9The line at the top of this page pins the label git:20260829.b60f9b2, 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_vwnqgwpfrniqdq52)
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Versions
The registry has recorded 1 version of this file, committed on Aug 29, 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 (9696 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_vwnqgwpfrniqdq52 GET https://markdownregistry.com/api/v1/resolve?ref=unboundcompute/security-agent-skills/auditing-jwt-verification-and-key-trust GET https://markdownregistry.com/api/v1/blob/8858cbd9eb1343e93b31ff0fbc6c180a3b613c58a7c702606502d99084c18af2
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.