Suspicious Inbox Manipulation Rules — 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: e0420451e21bb65a37161105c3ed3b637ad834e313fcf7cbcd01bba5348b4144

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 Manipulation Rules
id: ceb55fd0-726e-4656-bf4e-b585b7f7d572
status: test
description: Detects suspicious rules that delete or move messages or folders are set on a user's inbox.
references:
    - https://learn.microsoft.com/en-us/entra/id-protection/concept-identity-protection-risks#suspicious-inbox-manipulation-rules
    - 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.stealth
    - attack.t1140
logsource:
    product: azure
    service: riskdetection
detection:
    selection:
        riskEventType: 'mcasSuspiciousInboxManipulationRules'
    condition: selection
falsepositives:
    - Actual mailbox rules that are moving items based on their workflow.
level: high

Original YAML and metadata in JSON

False positives

• Actual mailbox rules that are moving items based on their workflow.

Source references

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