This rule targets O365 accounts with an unusually high number of failed authentication attempts, specifically more than 20 within a 5-minute window. The detection uses Unified Audit Logs, specifically monitoring for 'UserLoginFailed' events which are indicative of authentication issues. This pattern may suggest malicious activity, such as brute force attacks or attempts to guess passwords. Such unauthorized access attempts pose significant risks, potentially allowing attackers to compromise sensitive data stored within the O365 environment, including emails and documents. Immediate investigation is advised when this threshold is exceeded to mitigate potential data breaches and unauthorized access.