What it is
Credential stuffing is an automated attack where adversaries take breached login credentials—often harvested from a previous Data Breach—and reuse them against other platforms. Because many people recycle passwords, even unrelated services can be compromised once those credentials leak. Attackers rely on botnets and scripting frameworks that can replay thousands of username and password combinations per minute across login pages, APIs, mobile apps, and administrative portals, frequently chaining the activity with Brute Force Attack tooling for speed and evasion.
Why it matters
Credential stuffing is one of the leading causes of account takeover, fraudulent transactions, and unauthorized access to business systems. Organizations with customer portals, SaaS dashboards, or remote access services are frequent targets, and the surge of automated traffic can degrade performance or lock out legitimate users. Without monitoring for leaked credentials or unusual login patterns, businesses may remain unaware that employee or customer accounts have already been compromised elsewhere—escalating compliance exposure and incident response costs.
How to reduce risk
- Enforce Multi-Factor Authentication (MFA) on every sensitive login, especially admin and remote access accounts.
- Monitor the external attack surface for leaked or reused credentials and take action when matches appear.
- Apply rate limiting, bot detection, and IP reputation controls to login and API endpoints.
- Educate users to avoid password reuse and adopt password managers or passkeys.
- Consider passwordless or phishing-resistant authentication where possible.
- Detect anomalous access such as rapid login attempts, impossible travel, or unexpected autonomous traffic sources.