Microsoft 365 - User Restricted from Sending Email

Status: test
Severity: medium
Log source: product m365, service threat_management
Author: austinsonger
Source: github.com/SigmaHQ/sigma

Detects when a Security Compliance Center reported a user who exceeded sending limits of the service policies and because of this has been restricted from sending email.

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1199` Trusted Relationship

Telemetry coverage

Platform	Record / event type
Microsoft 365	User restricted from sending email

Rules detecting the same action

These rules filter on the same operation.

Deprecated - M365 Security Compliance User Restricted from Sending Email (Elastic)

Rule body

title: Microsoft 365 - User Restricted from Sending Email
id: ff246f56-7f24-402a-baca-b86540e3925c
status: test
description: Detects when a Security Compliance Center reported a user who exceeded sending limits of the service policies and because of this has been restricted from sending email.
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
author: austinsonger
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

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    eventSource: SecurityComplianceCenter
    eventName: 'User restricted from sending email'
    status: success

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`eventName`	eq	`User restricted from sending email`	`field:"aws::eventName" kind:eq value:"User restricted from sending email"`
`eventSource`	eq	`SecurityComplianceCenter`	`field:"aws::eventSource" kind:eq value:"SecurityComplianceCenter"`
`status`	eq	`success`	`field:"status" kind:eq value:"success"`