Broken Authentication occurs when applications or APIs incorrectly implement authentication mechanisms, allowing adversaries to compromise credentials, bypass authentication controls, or impersonate other users. Common causes include weak password storage, predictable session tokens, missing multi-factor authentication, and flaws in token or session lifecycle management. Exploitation can lead to full account takeover and lateral movement within systems.

Remediation

• Use secure, industry-standard authentication protocols (e.g., OAuth 2.0, OpenID Connect) with strict server-side validation of tokens.
• Enforce secure credential handling: store passwords using strong adaptive hashing algorithms (e.g., bcrypt, Argon2) with unique per-user salts.
• Implement short-lived, signed access tokens (e.g., JWT with audience/issuer claims) with secure refresh workflows; revoke tokens immediately upon logout, password reset, or compromise.
• Apply rate limiting, exponential backoff, and account lockout policies for repeated failed login attempts.
• Require multi-factor authentication (MFA) for sensitive operations and administrative access.
• Protect session identifiers using the `HttpOnly`, `Secure`, and `SameSite` cookie attributes.