Teams External Guest Added Followed by Bulk File Access
Detects anomalous activity by newly added guest users in Microsoft Teams, specifically identifying when a guest user account is added and subsequently performs multiple file-related operations (upload, download, access) or message-sending activities within a short timeframe. This behavior can be indicative of external threat actors or compromised guest accounts exfiltrating or accessing sensitive information within a Teams workspace.
Microsoft Sentinel (KQL)

