Best practices for secure user authentication

Authentication is a crucial component of application security, often prone to vulnerabilities despite its importance. Stolen credentials contribute to a significant percentage of web attacks, resulting in costly breaches. Fortunately, authentication protocols and practices have matured, offering stable solutions. Recommended protocols include OAuth 2.1 with PKCE, OpenID Connect for user identity, and SAML 2.0 for enterprise needs. WebAuthn and passkeys are suggested for passwordless authentication, enhancing security by eliminating shared secrets and improving user experience. When passwords are necessary, modern hashing algorithms like Argon2id or bcrypt should be used to prevent vulnerabilities. Password policies should focus on length rather than complexity, and MFA should be layered, favoring phishing-resistant methods. Sessions should use short-lived access tokens with refresh token rotation to mitigate risks. JWTs require thorough validation, and the storage of tokens should consider security threats, favoring HttpOnly cookies and memory storage. Rate limiting, account enumeration prevention, and secure password reset processes are essential defenses. Comprehensive logging of authentication events helps detect breaches early. Building custom authentication systems is feasible but comes with high risks and resource costs, making third-party solutions like WorkOS a viable option for many teams.