Microsoft 365 SecurityComplianceCenter: User Restricted From Sending Email

Alerts when Microsoft 365 SecurityComplianceCenter reports a user was successfully restricted from sending email due to sending-limit policy violations.

FreeReviewedSigma · Medium · v4
Product
m365
Service
threat_management
Author
austinsonger (SigmaHQ), DRL 1.1
Published
2021-08-19
Updated
2026-07-31
title: "Microsoft 365 SecurityComplianceCenter: User Restricted From Sending Email"
id: e4df2531-0104-451c-a099-49a1885b5400
status: test
description: This rule triggers when the Security Compliance Center reports a successful event indicating a user was restricted from sending email after exceeding sending limits under service policies. Such restrictions can be abused to disrupt communications or to prevent legitimate sending, so alerting on these enforcement actions helps security teams validate policy outcomes and investigate impacted accounts. It relies on threat management telemetry from Microsoft 365 with event source SecurityComplianceCenter and the specific event name 'User restricted from sending email' with successful status.
references:
  - https://learn.microsoft.com/en-us/defender-cloud-apps/anomaly-detection-policy
  - https://learn.microsoft.com/en-us/defender-cloud-apps/policy-template-reference
  - https://github.com/SigmaHQ/sigma/blob/master/rules/cloud/m365/threat_management/microsoft365_user_restricted_from_sending_email.yml
author: austinsonger, Huntrule Team
date: 2021-08-19
modified: 2022-10-09
tags:
  - attack.initial-access
  - attack.t1199
logsource:
  service: threat_management
  product: m365
detection:
  selection:
    eventSource: SecurityComplianceCenter
    eventName: User restricted from sending email
    status: success
  condition: selection
falsepositives:
  - Unknown
level: medium
license: DRL-1.1
related:
  - id: ff246f56-7f24-402a-baca-b86540e3925c
    type: derived