Broken Authentication Testing

Broken Authentication Testing is a skill for Claude Code, Codex from cgyudistira/agentkit. It costs 67 tokens per session (3,045 once invoked), scanned A, a copy of broken-authentication, MIT.

A security-testing guide for finding weaknesses in login and session systems, including passwords, multi-factor authentication, cookies, and tokens.

In plain words
What is it for?
Use it to test password rules, credential-guessing resistance, multi-factor authentication, session fixation, token security, and session timeouts—with written permission.
Why use it?
It helps identify ways an attacker could bypass login, take over accounts, or misuse sessions before those weaknesses cause harm.

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/cgyudistira/agentkit/broken-authentication
Any agent
npx skills add cgyudistira/agentkit --skill broken-authentication
Clone the repo
git clone --depth 1 https://github.com/cgyudistira/agentkit

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for Broken Authentication Testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/cgyudistira/agentkit/broken-authentication.svg)](https://agentmods.dev/skills/cgyudistira/agentkit/broken-authentication)
Your own site
<a href="https://agentmods.dev/skills/cgyudistira/agentkit/broken-authentication"><img src="https://agentmods.dev/badge/skills/cgyudistira/agentkit/broken-authentication.svg" alt="Measured on agentmods" height="20"></a>
Per session 67 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,045 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00067 $0.03045
Opus 5 $0.00034 $0.01522
Sonnet 5 $0.00013 $0.00609
Haiku 4.5 $0.00007 $0.00304

Measured 3d ago against content hash 70ff7a295178, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

Broken Authentication Testing 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 3d 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.

response = requests.get("https://target.com/login")
Origin

This is a copy

92% identical to broken-authentication — 2 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.

templates/skills/broken-authentication/SKILL.md · 477 lines

How it starts

The opening of the file, as written. The whole thing — 477 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Broken Authentication Testing

Purpose

Identify and exploit authentication and session management vulnerabilities in web applications. Broken authentication consistently ranks in the OWASP Top 10 and can lead to account takeover, identity theft, and unauthorized access to sensitive systems. This skill covers testing methodologies for password policies, session handling, multi-factor authentication, and credential management.

Prerequisites

Required Knowledge

  • HTTP protocol and session mechanisms
  • Authentication types (SFA, 2FA, MFA)
  • Cookie and token handling
  • Common authentication frameworks

Required Tools

  • Burp Suite Professional or Community
  • Hydra or similar brute-force tools
  • Custom wordlists for credential testing
  • Browser developer tools

Required Access

  • Target application URL
  • Test account credentials
  • Written authorization for testing

Outputs and Deliverables

  1. Authentication Assessment Report - Document all identified vulnerabilities
  2. Credential Testing Results - Brute-force and dictionary attack outcomes
  3. Session Security Analysis - Token randomness and timeout evaluation
  4. Remediation Recommendations - Security hardening guidance

Core Workflow

Phase 1: Authentication Mechanism Analysis

Understand the application's authentication architecture:

# Identify authentication type
- Password-based (forms, basic auth, digest)
- Token-based (JWT, OAuth, API keys)
- Certificate-based (mutual TLS)
- Multi-factor (SMS, TOTP, hardware tokens)

# Map authentication endpoints
/login, /signin, /authenticate
/register, /signup
/forgot-password, /reset-password
/logout, /signout
/api/auth/*, /oauth/*

Capture and analyze authentication requests:

POST /login HTTP/1.1
Host: target.com
Content-Type: application/x-www-form-urlencoded

username=test&password=test123

Phase 2: Password Policy Testing

Evaluate password requirements and enforcement:

# Test minimum length (a, ab, abcdefgh)
# Test complexity (password, password1, Password1!)
# Test common weak passwords (123456, password, qwerty, admin)
# Test username as password (admin/admin, test/test)

Read the full file on GitHub · 477 lines

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. 3d ago First seen · 477 lines · 67 tokens per session scan A 70ff7a295178

Subscribe to this mod's changes

Broken Authentication Testing is a skill published in the GitHub repository cgyudistira/agentkit (2 stars, last pushed 6mo ago), licensed MIT. It adds 67 tokens to every session and 3,045 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). It is 92% identical to broken-authentication, differing in 2 lines, and is treated as a copy.

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