What is credential stuffing, and how do you stop it?
2 min read · Updated October 15, 2026
Credential stuffing is an automated attack where criminals try email and password pairs from old breaches on other websites. It succeeds when people reuse passwords. Unique passwords per account and two-factor authentication stop it, even if your details are already leaked.
How the attack works
Attackers collect leaked login pairs. They use software to try each pair against popular services, such as email, shopping, streaming and banking sites, thousands of times per hour. Even a tiny success rate yields many compromised accounts.
Why it keeps working
Reuse. If a person uses the same password on a small forum and on their email, the forum’s breach becomes an email takeover. The attacker never has to ‘hack’ anything; they simply log in.
Is your login already in a leak?
Strong habits help most when you know which accounts are already exposed. Check your email address for free.
Signs you may have been hit
- ✓Login alerts from places or devices you do not recognise.
- ✓Password reset emails you did not request.
- ✓Orders, messages or changes you did not make.
- ✓Being locked out after repeated failed logins.
How to protect yourself
- ✓Use a unique password for each account.
- ✓Enable two-factor authentication.
- ✓Check your email for breaches and replace exposed passwords.
- ✓Delete old accounts you no longer use.
Frequently asked questions
Is credential stuffing the same as brute force?+
No. Brute force guesses passwords. Credential stuffing uses real leaked passwords against other sites.
Can 2FA stop it?+
Yes, in most cases. The attacker has the password but not your second factor.
Does it only target big companies?+
No. Any account, personal or business, can be tried against leaked credentials.
Stop guessing. Check your email in seconds.
The free Leakill check looks for your email address in known breach records and tells you whether it was exposed. If it was, an optional detailed report lists the incidents, dates, sources, the kinds of data involved and practical next steps. It is a one-off report, not a subscription.
A breach match is a warning signal, not proof that someone has access to your account today. No public database covers every breach, so a clean result lowers risk without guaranteeing safety.