High-volume anonymous-proxy exfiltration across SharePoint/OneDrive/Exchange
This rule detects anomalous activity where users access Microsoft 365 services (SharePoint, OneDrive, Exchange) through identified anonymous proxy connections. It identifies potentially malicious exfiltration or bulk activity by flagging users who perform a high number of operations (1,000+ events) or download a significant volume of data (5GB+) within a 2-hour window.
Splunk (SPL)
