Credential Stuffing
Credential stuffing is an attack where stolen username-password pairs from data breaches are automatically tested against other services, exploiting the fact that many people reuse passwords.
What Is Credential Stuffing?
Credential stuffing is a type of cyberattack in which an attacker takes large lists of username-password combinations, usually obtained from previous data breaches, and uses automated tools to try them against login pages of other services. The attack exploits a simple human weakness: password reuse. Studies consistently show that over 60% of people use the same password across multiple sites, making credential stuffing alarmingly effective.
How the Attack Works
Attackers purchase or download breach databases containing millions of credentials. They then feed these into bot software that automates login attempts at high speed. To avoid detection, they route traffic through residential proxies or backconnect proxies so each attempt appears to originate from a different IP address. Successful logins lead to account takeover, where the attacker gains access to the victim's account on the target service.
The Scale of the Problem
Major platforms report billions of credential stuffing attempts per year. The financial impact extends beyond direct fraud: account lockouts frustrate legitimate users, incident response consumes engineering resources, and breaches damage brand reputation. Industries particularly targeted include banking, e-commerce, streaming services, and gaming platforms.
Defending Against Credential Stuffing
Effective defense is multi-layered. Rate limiting slows down automated attempts. CAPTCHAs add friction that bots must overcome. Device fingerprinting identifies suspicious patterns across login sessions. AntiProxies contributes a critical layer by identifying when login attempts originate from proxies, VPNs, or known botnet infrastructure, allowing your security systems to flag or block these high-risk connections before credentials are tested. See the hidden cost of bot traffic for the broader financial impact of automated attacks on your business.