Credential Stuffing
Credential stuffing uses previously exposed username/password pairs against other services, relying on password reuse.
Mechanism
The attacker automates authentication attempts with credentials obtained from unrelated breaches. It differs from brute force because the candidate passwords are already known.
Indicators to watch
Many accounts targeted from distributed sources, login success after a low number of attempts per account, impossible-travel patterns, and authentication attempts using known breached passwords.
Concept diagram
Defensive controls
Require MFA, block known compromised passwords, use bot/risk-based controls, rate-limit authentication, monitor impossible travel, and encourage unique passwords with password managers.
Recommended security control
Entra ID / identity protection
Use test credentials and a local identity provider for demonstrations.
Defense tool
The administrator has not attached a tool yet. This slot will show “Build Soon” until a link or file is configured.
All attack descriptions are for defensive education. Test scanning, traffic generation, interception, wireless testing, and vulnerable applications only on systems and networks you own or are explicitly authorized to assess.