jwt-scan

An offline command for inspecting and testing JSON Web Tokens (JWTs), signed data commonly used to prove a user's identity or permissions between web services.

In plain words
What is it for?
Analyzing token claims, testing an unsigned-token flaw, testing confusion between RSA and HMAC signing, and trying a wordlist against weak HMAC secrets.
Why use it?
It helps security testers check whether token verification accepts unsafe signing settings, weak secrets, or claims such as administrator roles without needing network access.

Command

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add commands/awarexone/agentic-bug-hunter/jwt-scan
Clone the repo
git clone --depth 1 https://github.com/Awarexone/Agentic-Bug-Hunter
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 543 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.00543
Opus 5 $0.00000 $0.00271
Sonnet 5 $0.00000 $0.00109
Haiku 4.5 $0.00000 $0.00054

Measured 2d ago against content hash 68398c49e8be, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

jwt-scan scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

commands/jwt-scan.md · 47 lines

What it actually says

/jwt-scan

Forge and analyze JWTs offline. Implements the three highest-paid JWT bugs from the auth skill. All crypto is pure stdlib — no network needed to mint a forgery.

Usage

/jwt-scan <token> --analyze
/jwt-scan <token> --alg-none
/jwt-scan <token> --confuse --public-key pub.pem --set role=admin
/jwt-scan <token> --crack --wordlist wordlists/jwt-secrets.txt

Run directly:

tools/jwt_scanner.py "$TOKEN" --analyze
tools/jwt_scanner.py "$TOKEN" --crack --wordlist secrets.txt

Attacks

Flag Attack When it works
--alg-none Strip signature, set alg to none/None/NONE/nOnE verifier honors alg from the header
--confuse --public-key RS256→HS256: re-sign with the server's public key as the HMAC secret verifier calls generic verify(token, key)
--crack --wordlist Brute-force the HS256 secret weak/guessable signing secret
--analyze Static: flags alg=none, missing exp, trust-bearing claims (role/is_admin/scope), kid (probe for traversal/SQLi) always

--set key=value (repeatable) overrides claims in --alg-none/--confuse forgeries — e.g. --set role=admin --set sub=1.

Workflow

  1. --analyze to read the header/claims and pick an attack.
  2. Mint a forgery (--alg-none or --confuse) with --set role=admin.
  3. Replay the forged token against an authenticated endpoint — if it's accepted, you have privilege escalation / auth bypass (Critical).

Getting the public key for --confuse: try /jwks.json, /.well-known/jwks.json, or extract it from the TLS cert / a verify endpoint.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 47 lines · 0 tokens per session scan A 68398c49e8be

Subscribe to this mod's changes

jwt-scan is a command published in the GitHub repository Awarexone/Agentic-Bug-Hunter (4,651 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 543 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other commands, from other repositories

recon

Run full recon pipeline on a target — subdomain enum (Chaos API + subfinder), live host discovery (dnsx + httpx), URL crawl (katana + waybackurls + gau), gf pattern classification, nuclei scan. Outputs to recon/ / directory. Usage: /recon target.com.

elementalsouls/Claude-BugHunter · 65 tokens

hunt

Active vulnerability hunting. Two-track dispatcher — asks Red Team vs WAPT, hands off to hunt-dispatch skill and sibling commands. Usage: /hunt target.com | /hunt .target.com | /hunt targets.txt [--vuln-class X] [--source-code P] [--chrome].

elementalsouls/Claude-BugHunter · 63 tokens

token-scan

Meme coin and token security scan — checks for rug pull vectors (hidden mint, honeypot, fee manipulation, LP lock bypass, authority retention, bonding curve exploits, fake renounce, sandwich amplification). Manual 8-class grep audit (with an optional automated scanner if present). Usage: /token-scan [--chain solana].

elementalsouls/Claude-BugHunter · 79 tokens

autopilot

Run autonomous hunt loop on a target — scope check → recon → rank surface → hunt → validate → report with configurable checkpoints. Usage: /autopilot target.com [--paranoid|--normal|--yolo].

elementalsouls/Claude-BugHunter · 49 tokens

triage

Quick 7-Question Gate triage on a finding before writing a report. Kills N/A submissions before they happen. Faster than /validate — for quick go/no-go decisions. Usage: /triage.

elementalsouls/Claude-BugHunter · 45 tokens

validate

Validate a finding — runs 7-Question Gate + 4-gate checklist. Kills weak findings before report writing. Prevents N/A submissions that hurt validity ratio. Usage: /validate.

elementalsouls/Claude-BugHunter · 41 tokens