A large number of failed login attempts from various IP addresses targeting different user accounts is indicative of a distributed brute-force attack. In this attack, the culprit is using multiple systems to try a wide range of password combinations in hopes of gaining unauthorized access to user accounts. The distributed nature of the attack, utilizing various IPs, helps in avoiding detection and bypassing account lockout policies. It's critical to spot this early on to implement measures such as account lockouts, IP restrictions, and strong password policies to prevent access.