Automated MFA Push Bombing via API

This rule detects automated multi-factor authentication (MFA) push bombing attempts targeting Duo Security's API. It specifically looks for HTTP POST requests to 'api.duosecurity.com' and triggers an alert if 10 such requests are observed from the same source IP within a 30-second window. This behavior is indicative of an attacker repeatedly sending MFA push notifications to a user's device in an attempt to overwhelm them or trick them into approving a fraudulent login.