auth-sec

An entry guide for checking authentication and authorization problems in software, including logins, sessions, tokens, and access between users or accounts.

In plain words
What is it for?
Use it to route testing for login, password reset, two-factor authentication, sessions, JWT, OAuth, SSO, CSRF, CORS, and cross-account access.
Why use it?
It helps choose the right security check before investigating a specific weakness. It separates problems such as login bypasses, unauthorized object access, browser attacks, and identity-provider errors.

Skill for Claude CodeCodex

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 skills/miru-zero/zero-brain/auth-sec
Any agent
npx skills add miru-zero/zero-brain --skill auth-sec
Clone the repo
git clone --depth 1 https://github.com/miru-zero/zero-brain

Made for: Claude Code, Codex.

Per session 46 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 561 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 92% copy Near-identical to another mod 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 $0.00046 $0.00561
Opus 5 $0.00023 $0.00280
Sonnet 5 $0.00009 $0.00112
Haiku 4.5 $0.00005 $0.00056

Measured yesterday against content hash 22b76c166b9e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

auth-sec 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 yesterday.

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.

Origin

This is a copy

92% identical to auth-sec — 6 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/auth-sec/SKILL.md · 39 lines

What it actually says

Authentication and Authorization Router

This is the routing entry point for authentication, sessions, and authorization boundaries.

Use it to decide whether the issue is mainly login mechanics, object-level authorization, browser trust boundaries, or identity protocols such as OAuth/JWT/SAML before going deeper.

When to Use

  • The target includes login, registration, password reset, 2FA, sessions, JWT, OAuth, or SSO
  • You suspect object authorization flaws, cross-tenant access, cross-origin reads, CSRF, or protocol misconfiguration
  • You need to decide whether to test authentication or authorization first

Skill Map

  1. First confirm the authentication model and session boundaries
  2. Then confirm object-level and function-level authorization
  3. Then move to token, cross-origin, and protocol details
  4. If enterprise federation exists, continue with OAuth, OIDC, or SAML topics
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. yesterday First seen · 39 lines · 46 tokens per session scan A 22b76c166b9e

Subscribe to this mod's changes

auth-sec is a skill published in the GitHub repository miru-zero/zero-brain (0 stars, last pushed 14d ago), licensed MIT. It adds 46 tokens to every session and 561 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 92% identical to auth-sec, differing in 6 lines, and is treated as a copy.

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