What is Credential Stuffing?
Turkish: Kimlik Bilgisi Doldurma (Credential Stuffing)
Credential stuffing is an account takeover attack that automatically tests leaked usernames and passwords across many services.
What is Credential Stuffing?
Credential stuffing uses username and password pairs leaked from other services and automatically tests them against a new target. The attacker is not guessing the password; they are relying on users reusing the same password across sites.
This makes it different from a classic brute force attack. Attempts per user may look low, but the total traffic can be high because attackers use large account lists and distributed proxy networks. Successful logins can lead to account takeover, order fraud, loyalty point theft, or personal data exposure.
How to Reduce Risk
Controls include rate limiting, bot behavior analysis, risk-based login checks, breached-password screening, device signals, and abnormal session alerts. 2FA or passkeys make account takeover harder even when a reused password is valid.
Organizations should avoid judging failed logins only by IP address. These attacks are often distributed, so user, device, ASN, country, user-agent, and velocity patterns need to be evaluated together. User notifications should explain password reset and session revocation steps clearly without causing unnecessary panic.
Related Terms
2FA adds a second proof, such as an authenticator app, SMS code, or security key, on top of a password during sign-in.
Brute Force AttackA brute force attack tries many password or key combinations automatically until one works, often targeting login and admin panels.
Rate LimitingRate limiting protects APIs by capping how many requests a user, IP address, or token can send within a defined time window.