How to Test Authentication and Authorization in Web and Mobile Apps

Introduction

Authentication and authorization are the gatekeepers of modern applications. Without robust testing, you risk exposing sensitive data, allowing privilege escalation, or even locking out legitimate users.

• Authentication verifies who a user is (e.g., login, SSO).
• Authorization defines what that user can do (e.g., access controls).

In this guide, we’ll walk through how to test authentication and authorization flows with real-world scenarios, test cases, automation tips, and best practices for bulletproof security and functionality.

Why Authentication and Authorization Testing Matters

• 🔐 Prevent Unauthorized Access Protect user data and internal systems.

• 🚫 Avoid Broken Access Control OWASP consistently lists this among the top security risks.

• ✅ Ensure Business Logic is Enforced Role-based and feature-level permissions must be validated.

• ⚙️ Support Regulatory Compliance GDPR, HIPAA, SOC 2, and ISO 27001 all require access control verification.

Common Authentication Methods to Test

Authorization Types to Test

• Role-Based Access Control (RBAC) Admin, user, guest, support, etc.

• Attribute-Based Access Control (ABAC) Based on metadata like department, subscription level, or geolocation.

• Resource-Level Permissions Access to specific documents, projects, accounts, or data rows.

Key Authentication Test Cases

Key Authorization Test Cases

Tools for Testing Authentication & Authorization

🔧 Automation & UI Testing

• Cypress / Playwright – Automate login forms, 2FA, redirects
• Selenium – For cross-browser UI auth flows
• Appium – Mobile app login and biometric testing

🔐 API & Security Testing

• Postman – For testing login, token handling, role-based API access
• Burp Suite – Intercept and manipulate auth tokens and cookies
• OWASP ZAP – Automated security scans

🧪 Mocks & Utilities

• Mock Service Worker (MSW) – Mock auth API calls
• MailSlurp / Mailosaur – Catch OTP or email verification tokens
• JWT.io – Inspect and debug JSON Web Tokens

Example: Automating Authentication with Cypress

describe('Login Flow', () => {
  it('Logs in with valid user credentials', () => {
    cy.visit('/login');
    cy.get('input[name="email"]').type('[email protected]');
    cy.get('input[name="password"]').type('SecurePass123!');
    cy.get('button[type="submit"]').click();

    cy.url().should('include', '/dashboard');
    cy.contains('Welcome, User').should('be.visible');
  });
});

Security Tests to Include

• ✅ Token Tampering Change JWT or access tokens and attempt access

• ✅ Session Expiry Ensure expired sessions redirect to login

• ✅ CSRF/XSS Protection Validate token-based CSRF handling for authenticated actions

• ✅ Privilege Escalation Attempts Test if a user can promote themselves by tampering with requests

• ✅ Role Fuzzing Try sending fake roles or permissions via request headers

Best Practices for Auth Testing

• 🔒 Always test over HTTPS (TLS)
• 🔁 Rotate tokens periodically (refresh tokens)
• 🧪 Use test accounts with every role type
• ⏱ Test login rate limits and brute-force protection
• 🧼 Sanitize and validate all inputs, even on login
• 🧩 Store secrets securely (e.g., in env variables or secret managers)
• 👩‍💻 Perform manual review of permission matrix annually

Common Bugs to Watch Out For

• Session not cleared on logout
• User can access unauthorized resources via URL
• Token reused after logout
• Role stored in client-side JS only (bypassed easily)
• Password reset link usable multiple times
• 2FA not enforced for sensitive roles

Conclusion

Authentication and authorization are not just security features—they’re business-critical functionality. Broken login or flawed access control can compromise your platform, your users, and your brand.

Call to Action: Integrate authentication and authorization testing into your CI/CD pipeline. Use a mix of UI, API, and security testing tools to keep your app safe and user-ready.

FAQs

Q: What’s the difference between authentication and authorization? A: Authentication verifies identity (login), while authorization controls access (permissions after login).

Q: Can I automate login flows with 2FA? A: Yes, with tools like MailSlurp (email) or custom test OTP endpoints.

Q: Should I test JWTs manually? A: Yes. Use JWT.io to inspect structure, verify claims, and validate expiration behavior.