A02:2021 Identification and Authentication Failures

December 23, 2021

A07:2021 — Identification and Authentication Failures

Permits automated attacks such as credential stuffing, where the attacker has a list of valid usernames and passwords.
Permits brute force or other automated attacks.
Permits default, weak, or well-known passwords, such as "Password1" or "admin/admin".
Uses weak or ineffective credential recovery and forgot-password processes, such as "knowledge-based answers," which cannot be made safe.
Uses plain text, encrypted, or weakly hashed passwords data stores (see A02:2021-Cryptographic Failures).
Has missing or ineffective multi-factor authentication.
Exposes session identifier in the URL.
Reuse session identifier after successful login.
Does not correctly invalidate Session IDs. User sessions or authentication tokens (mainly single sign-on (SSO) tokens) aren't properly invalidated during logout or a period of inactivity.

Where possible, implement multi-factor authentication to prevent automated credential stuffing, brute force, and stolen credential reuse attacks.
Do not ship or deploy with any default credentials, particularly for admin users.
Implement weak password checks, such as testing new or changed passwords against the top 10,000 worst passwords list.
Align password length, complexity, and rotation policies with National Institute of Standards and Technology (NIST) 800-63b's guidelines in section 5.1.1 for Memorized Secrets or other modern, evidence-based password policies.
Ensure registration, credential recovery, and API pathways are hardened against account enumeration attacks by using the same messages for all outcomes.
Limit or increasingly delay failed login attempts, but be careful not to create a denial of service scenario. Log all failures and alert administrators when credential stuffing, brute force, or other attacks are detected.
Use a server-side, secure, built-in session manager that generates a new random session ID with high entropy after login. Session identifier should not be in the URL, be securely stored, and invalidated after logout, idle, and absolute timeouts.