A system and method that detects malicious account creation in a web-based platform. A method includes detecting suspicious events associated with an account creation process using a username classifier that evaluates a username used to create a new account, an IP address classifier that evaluates an IP address used to create the new account, and a domain classifier that evaluates a domain from an email address used to create the new account; analyzing each detected suspicious event with a density analysis classifier to determine if each detected suspicious event comprises a malicious event based on a density of detected suspicious events from a collections of account creation processes; and determining an alert condition based on at least one malicious event detection.