Agent skill · security · yaklang
authbypass-authentication-flaws
Authentication bypass testing playbook. Use when assessing login flows, password reset logic, account recovery, MFA bypass, token predictability, brute-force resistance, and session boundary flaws.
Why this skill is useful
Adds detailed attack methodologies and executable testing procedures for various authentication bypass scenarios that are not commonly known.
What it needs
About 10k tokens when loaded. Last updated 2026-06-16. 1,563 stars on the source repository.
What this skill does
SKILL: Authentication Bypass — Expert Attack Playbook AI LOAD INSTRUCTION: Expert authentication bypass techniques. Covers SQL injection-based login bypass, password reset flaws, token predictability, account enumeration, brute force bypass, and multi-factor auth bypass. Distinct from JWT/OAuth (covered in ../jwt-oauth-token-attacks/SKILL.md). Focus on the login mechanism itself. 0. AUTHORIZED CREDENTIAL TEST PLANNING After reducing routing entries, default credentials, username variants, port focus, and wordlist sizing are handled here in one place. Service-first tiny sets Service Type First Usernames First Passwords --- --- --- phpMyAdmin root, admin empty, root, phpmyadmin, admin FTP ftp, admin, test empty, ftp, admin, 123456 SSH root, admin, service account names root, admin, seasonal variants MySQL root, mysql empty, root, mysql Tomcat / Java admin tomcat, admin, manager tomcat, admin, s3cret WebLogic weblogic, admin weblogic, welcome1, admin Username classes Class Examples --- --- Generic admins admin, administrator, root, test, guest Support / ops dev, ops, sysadmin, service, backup Name-based firstname, lastname, f.lastname, first.last Mail-derived left side of corporate email formats Product-based tomcat, weblogic, jenkins, gitlab Wordlist sizing and port focus Scenario Preferred Size Why --- --- --- Default admin panel 5 to 50 passwords Defaults beat giant lists here Internal service with known product vendor-specific small set Better signal than generic lists Consumer login with weak controls Top 20 or Top 100 Fast verification Rate-limited login tiny list + header/rotation strategy Preserve attempts Offline hash cracking large dictionaries Online brute rules do not apply Prioritize common ports and service surfaces: 80/443/8080/8443 admin panels, 22 SSH, 21 FTP, and 3306/5432/6379/27017 data or management services. --- 1. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills yaklang/authbypass-authentication-flaws