Mail Forwarding/Redirecting Activity In O365

SigmaHQ Detections@sigmaHQ

•updated Nov 17, 2024•0•50

This rule detects the creation or modification of email forwarding or redirection rules within Microsoft 365 audit logs. It specifically looks for operations related to 'UpdateInboxRules', 'Set-Mailbox', 'New-InboxRule', and 'Set-InboxRule' that include parameters indicative of forwarding or redirecting emails, such as 'Forward', 'Recipients', 'ForwardingSmtpAddress', 'ForwardingAddress', 'ForwardAsAttachmentTo', 'ForwardTo', 'RedirectTo', and 'RedirectToRecipients'. This activity can be a sign of an attacker attempting to exfiltrate sensitive information from a compromised mailbox or maintain persistence.