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Credential Stuffing

Credential stuffing is an automated attack that uses stolen username/password combinations from previous data breaches to gain unauthorized access to user accounts. It exploits the common practice of password reuse across multiple services.

How credential stuffing works

Attackers obtain large databases of stolen credentials from previous data breaches (often available on dark web marketplaces). Using automated tools and botnets, they systematically try these credentials against target login pages. Because many people reuse passwords, a significant percentage of attempts succeed. Successful logins give attackers access to accounts that may contain sensitive data, stored payment methods, or further credentials.

Impact on businesses

Account takeover leading to fraud, unauthorized purchases, or data theft. Financial losses from fraudulent transactions. Customer trust erosion and reputational damage. Increased customer support costs from account lockouts. Regulatory exposure if compromised accounts contain personal data. High volumes of automated login attempts can also degrade system performance.

Prevention measures

Implement multi-factor authentication (MFA) to neutralize stolen passwords. Use rate limiting and CAPTCHA on login pages. Deploy bot detection and management solutions. Monitor for credential leaks affecting your organization's users. Implement breached password detection (checking passwords against known breach databases). Use risk-based authentication that challenges suspicious login attempts. Educate users about password reuse risks and promote password managers.

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