Credential Stuffing: Your Leaked Password Is Being Tested on Every Account You Own Right Now

Credential stuffing is an automated account-takeover technique where attackers leverage username/password pairs stolen from past data breaches to gain unauthorized access to other online services; this report explains how such attacks operate, compares them to brute-force methods, describes impacts on individuals and organizations, lists detection signs, and recommends mitigations (unique passwords, password managers, MFA, rate limiting, CAPTCHA and bot detection).