What Is Credential Stuffing? Attackers Don’t Crack Passwords, They Buy Them

This report explains credential stuffing as an industrialized, automated attack that leverages credentials harvested by infostealer malware and aggregated breach databases (combolists) to compromise accounts at scale; it highlights 2025 statistics (including a 16 billion credential dataset, 22% of breaches linked to stolen credentials, and a 160% surge in theft), provides technical anatomy of attacks and proxy/CAPTCHA evasion techniques, presents real-world case studies with financial and data loss, and recommends platform-level defenses such as enforced MFA, platform-wide authentication analytics, breached-password checks, bot detection, and continuous dark-web monitoring.