hunt-jwt-crypto SKILL.md skillA
hunt-jwt-crypto from novaestellar/novahaku is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add novaestellar/novahaku/hunt-jwt-crypto@git:20260910.546fe86Pins git:20260910.546fe86 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- novaestellar/novahaku
- Path
testing/hunt/hunt-jwt-crypto/SKILL.md- Versions recorded
- 3
- Latest version
- git:20260910.546fe86, committed Sep 10, 2026
- First version recorded
- Sep 3, 2026
- Size
- 9,174 bytes
- Repository stars
- 28
- License
- MIT
Hunt JWT cryptographic failures — alg:none signature-stripping and RS256→HS256 key-confusion that let an attacker forge a token for any identity (e.g. an admin) without knowing a secret. Use when the app authenticates with a JSON Web Token (an `eyJ...` Bearer token in the Authorization header, a cookie, or a login response). This skill OWNS JWT signature/crypto forgery (alg:none, key confusion, kid/jku header injection); hunt-ato covers JWT as one ATO path, hunt-auth-bypass covers SSO/SAML…
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
# HUNT-JWT-CRYPTO — Forgeable JSON Web Tokens (A04 Cryptographic Failures) ## What actually pays A JWT is `header.payload.signature`, each base64url. The signature is the only thing stopping you from editing the payload (your identity/role) and replaying it. It pays **High/Critical** when the verifier can be tricked into accepting a token you forged — so you become another user or an admin without their secret. Two classic, generic verifier flaws: - **`alg:none`** — the verifier trusts the token's own `alg` header. Set `alg:"none"`, drop the signature, edit the payload (e.g. `role:"admin"`, another user's `id`/`email`). A broken verifier skips signature checking. - **RS256 → HS256 key confusion** — the token is signed RS256 (asymmetric). The RSA **public** key is, by definition, public. If the verifier lets you choose HS256, it will use that public key as the HMAC *secret* — which you also know. Sign an edited payload with HS256 using the public key and it validates. ## Recon — is this app JWT-based? ``` Login/token responses containing "token":"eyJ..." or Set-Cookie: token=eyJ... Authorization: Bearer eyJ... on authenticated requests …
Read the whole file at its exact version.
How to install
mdr add novaestellar/novahaku/hunt-jwt-crypto@sha256:baade82394d43b29The line at the top of this page pins the label git:20260910.546fe86, 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_kfopon3hofbdmbtn)
6 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 3 versions of this file, between Sep 3, 2026 and Sep 10, 2026, about one every 3 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260910.546fe86 latest | 2026-09-10 | 546fe86 | 9,174 B | A | view · diff |
| git:20260903.29924dd | 2026-09-03 | 29924dd | 9,186 B | A | view · diff |
| git:20260903.fa855c4 | 2026-09-03 | fa855c4 | 9,157 B | A | view |
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 (9174 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
novaestellar/novahaku · 28 stars · license MIT · pushed 2026-09-28 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_kfopon3hofbdmbtn GET https://markdownregistry.com/api/v1/resolve?ref=novaestellar/novahaku/hunt-jwt-crypto GET https://markdownregistry.com/api/v1/blob/baade82394d43b29fcde6429b5dc3ca99353d3324d1d4b3c08c276db62c539d6
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.