Credential Stuffing and Password Spraying

Credential stuffing is an automated attack that takes username/password pairs stolen from one data breach and tries them on other services. It exploits password reuse — if someone uses the same password everywhere, one breach compromises all accounts.

Billions of credentials are available for purchase on dark web markets and forums. Tools like Sentry MBA, SNIPR, and custom Python scripts automate testing thousands of credential pairs per minute across many services simultaneously.