How secure is Firebase Authentication?

Firebase Authentication provides secure identity management with support for email/password, OAuth providers, phone auth, and anonymous auth. The service handles token generation, session management, and password hashing automatically. However, authentication alone does not protect your data since security rules must verify the auth token on every database and storage operation. Common issues include not enabling email verification, allowing anonymous auth without restricting what anonymous users can do, and not implementing proper account deletion flows. UNPWNED checks your authentication configuration alongside your security rules to ensure they work together to protect user data.