Credential stuffing is an automated attack that tests leaked username-and-password pairs against other services. Repeated invalid credentials in a login form can signal this threat rather than an ordinary user mistake. section 7.2.3
Treat repeated credential failures as actionable when they suggest an abnormal security event:
- Log the event rather than allowing security-relevant failures to disappear among routine input mistakes. section 7.2.3
- Monitor the resulting records and address suspected activity immediately. section 7.2.3


