Azure risk event: Suspicious inbox manipulation rules that delete or move messages or folders

Alerts on Azure risk events for suspicious inbox rules that delete or move mailbox items.

FreeReviewedSigma · High · v5

Product: azure
Service: riskdetection
Author: Mark Morowczynski '@markmorow', Gloria Lee, '@gleeiamglo' (SigmaHQ), DRL 1.1
Published: 2023-09-03
Updated: 2026-07-31

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1140Deobfuscate/Decode Files or Information
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags an Azure risk detection event indicating suspicious inbox manipulation rules that delete or move messages or folders within a user’s inbox. Attackers can use inbox rules to hide their activity, reroute communications, or degrade user visibility while maintaining persistence. The detection relies on Azure risk telemetry with the riskEventType value mcasSuspiciousInboxManipulationRules.

Reporting behind it

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Azure risk event: Suspicious inbox manipulation rules that delete or move messages or folders

Pivot detection · T1140 · 9 related

Changelog

v5
Candidate ingested via manual entry.2026-07-31
v4
Candidate ingested via manual entry.2026-07-31
v3
Candidate ingested via manual entry.2026-07-31
v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

azure-risk-detection-suspicious-inbox-manipulation-rules-set-to-delete-or-move-i-ceb55fd0

title: "Azure risk event: Suspicious inbox manipulation rules that delete or move messages or folders"
id: 2f580dbd-0e59-4acd-9b82-42b2019cf275
status: test
description: This rule flags an Azure risk detection event indicating suspicious inbox manipulation rules that delete or move messages or folders within a user’s inbox. Attackers can use inbox rules to hide their activity, reroute communications, or degrade user visibility while maintaining persistence. The detection relies on Azure risk telemetry with the riskEventType value mcasSuspiciousInboxManipulationRules.
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
  - https://github.com/SigmaHQ/sigma/blob/master/rules/cloud/azure/identity_protection/azure_identity_protection_inbox_manipulation.yml
author: Mark Morowczynski '@markmorow', Gloria Lee, '@gleeiamglo', Huntrule Team
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
license: DRL-1.1
related:
  - id: ceb55fd0-726e-4656-bf4e-b585b7f7d572
    type: derived

Convert

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