Test the auth failures attackers try first - shippingszn launch readiness

Happy-path auth testing proves almost nothing. The dangerous bugs are in the weird edges: wrong codes, fake emails, repeated attempts, duplicate signup, expired links, and users opening links on a different device.

Attackers probe the failure paths first because they reveal whether an account exists, whether a code can be brute-forced, and whether a user can get locked out. Paid users hit the same paths accidentally on launch day.

Owner verification required: Auth failure behavior requires a live auth provider, delivered emails/SMS, real browser sessions, and throwaway accounts. The scanner can flag code signals, but it cannot honestly click links, trigger provider lockouts, or verify copy in every failure state.

The Launch Fix Kit keeps scan-specific findings, file and line evidence, AI-builder punch-list tasks, and verification steps tied to the paid report.

Try the wrong password, magic code, or OTP 5-6 times. Confirm a real limit kicks in and the message stays generic.
Start password reset or magic-link login for an email that does not exist. The response should look like success, not 'account not found.'
Click the same verification/magic link twice and after expiry. It should recover gracefully, not show a stack trace or reveal internals.
Sign up with an email or phone that already exists. Confirm the provider's safe default copy and rate limits are used.
Record the exact pass/fail evidence in the launch report so nobody hand-waves auth as 'probably fine.'

Run the scanner | Unlock Launch Fix Kit

Canonical URL: https://shippingszn.com/i/auth-failure-cases/