diff --git a/rules-threat-hunting/cloud/m365/audit/microsoft365_susp_email_forwarding_activity.yml b/rules-threat-hunting/cloud/m365/audit/microsoft365_susp_email_forwarding_activity.yml index ab06ca589..c0a2ec12a 100644 --- a/rules-threat-hunting/cloud/m365/audit/microsoft365_susp_email_forwarding_activity.yml +++ b/rules-threat-hunting/cloud/m365/audit/microsoft365_susp_email_forwarding_activity.yml @@ -4,8 +4,10 @@ status: test description: Detects email forwarding or redirecting acitivty in O365 Audit logs. references: - https://redcanary.com/blog/email-forwarding-rules/ + - https://github.com/PwC-IR/Business-Email-Compromise-Guide/blob/fe29ce06aef842efe4eb448c26bbe822bf5b895d/PwC-Business_Email_Compromise-Guide.pdf author: RedCanary Team (idea), Harjot Singh @cyb3rjy0t date: 2023-10-11 +modified: 2024-11-17 tags: - attack.exfiltration - attack.t1020 @@ -31,9 +33,12 @@ detection: - 'New-InboxRule' - 'Set-InboxRule' Parameters|contains: - - 'ForwardTo' - 'ForwardAsAttachmentTo' + - 'ForwardingAddress' + - 'ForwardingSmtpAddress' + - 'ForwardTo' - 'RedirectTo' + - 'RedirectToRecipients' condition: 1 of selection_* falsepositives: - False positives are expected from legitimate mail forwarding rules. You need organisation specific knowledge. Filter out the domains that are allowed as forwarding targets as well as any additional metadata that you can use for exclusion from trusted sources/targets in order to promote this to a potential detection rule.