What Is a Brute Force Attack and How to Prevent It

This report outlines how brute force attacks (including dictionary, hybrid, reverse brute force, credential stuffing, and password spraying) are executed and remain effective, highlights recent real-world campaigns — notably a 130,000-device botnet targeting Microsoft 365 and an UNC5537 campaign against Snowflake that exploited non-interactive sign-ins to bypass MFA — and summarizes defensive controls such as strong password policies, MFA, rate limiting, monitoring, and protections for password hashes.