Suspicious Inbox Forwarding Identity Protection — Sigma Rule

Rule metadata and linked tags

Author: Mark Morowczynski '@markmorow', Gloria Lee, '@gleeiamglo'. Source status: test; severity: high. Source dates: 2023-09-03 / not supplied.

{
  "product": "azure",
  "service": "riskdetection"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 749be749f4347af6a3031edd95c8038550c5e9779c3f138b243e7508218b6504

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Suspicious Inbox Forwarding Identity Protection
id: 27e4f1d6-ae72-4ea0-8a67-77a73a289c3d
status: test
description: Indicates suspicious rules such as an inbox rule that forwards a copy of all emails to an external address
references:
    - https://learn.microsoft.com/en-us/entra/id-protection/concept-identity-protection-risks#suspicious-inbox-forwarding
    - https://learn.microsoft.com/en-us/entra/architecture/security-operations-user-accounts#unusual-sign-ins
author: Mark Morowczynski '@markmorow', Gloria Lee, '@gleeiamglo'
date: 2023-09-03
tags:
    - attack.t1114.003
    - attack.collection
logsource:
    product: azure
    service: riskdetection
detection:
    selection:
        riskEventType: 'suspiciousInboxForwarding'
    condition: selection
falsepositives:
    - A legitimate forwarding rule.
level: high

Original YAML and metadata in JSON

False positives

• A legitimate forwarding rule.

Source references

• https://learn.microsoft.com/en-us/entra/id-protection/concept-identity-protection-risks#suspicious-inbox-forwarding
• https://learn.microsoft.com/en-us/entra/architecture/security-operations-user-accounts#unusual-sign-ins