M365 Defender Alerts Signal (UAL)

Identifies alerts generated by Microsoft Defender products including Windows Defender for Endpoint (WDATP), Microsoft Cloud App Security (MCAS), Microsoft Defender for Identity, Microsoft 365 Defender custom detections, and Defender Experts for XDR via M365 Unified Audit Logs (UAL). These cross-platform alerts indicate detected threats across endpoints, cloud applications, and identity systems. This building block rule generates security events for correlation, threat hunting, and telemetry collection to support comprehensive threat detection.

Rule type: query
Rule indices:

• logs-o365.audit-*

Rule Severity: medium
Risk Score: 47
Runs every:
Searches indices from: now-9m
Maximum alerts per execution: 100
References:

• https://learn.microsoft.com/en-us/defender-endpoint/
• https://learn.microsoft.com/en-us/defender-cloud-apps/
• https://learn.microsoft.com/en-us/defender-for-identity/
• https://learn.microsoft.com/en-us/office/office-365-management-api/office-365-management-activity-api-schema#enum-auditlogrecordtype---type-edmint32

Tags:

• Domain: Cloud
• Domain: SaaS
• Domain: Endpoint
• Data Source: Microsoft 365
• Data Source: Microsoft 365 Audit Logs
• Data Source: Microsoft Defender XDR
• Data Source: Microsoft Defender for Cloud Apps
• Data Source: Microsoft Defender for Identity
• Use Case: Threat Detection
• Tactic: Initial Access
• Tactic: Execution
• Tactic: Defense Evasion
• Rule Type: BBR

Version: 3
Rule authors:

• Elastic

Rule license: Elastic License v2

For information on troubleshooting the maximum alerts warning please refer to this guide.

This rule identifies Microsoft Defender alerts forwarded through the Microsoft 365 Unified Audit Log (logs-o365.audit-*). For alerts and incidents ingested directly from the Microsoft Defender XDR integration data streams (logs-m365_defender.alert-* and logs-m365_defender.incident-*), enable the corresponding promotion rules instead:

• Microsoft Defender XDR Alert External Alerts (rule_id: c2a0e42b-ac3d-468f-82a5-0082066e1b59)
• Microsoft Defender XDR Incident External Alerts (rule_id: 3c99579e-6491-4562-87f4-4d10f0a822b4)

event.dataset:o365.audit and
    event.code:(WDATPAlerts or MCASAlerts or MicrosoftDefenderForIdentityAudit or MS365DCustomDetection or DefenderExpertsforXDRAdmin)
		

Framework: MITRE ATT&CK

• Tactic:
  • Name: Initial Access
  • Id: TA0001
  • Reference URL: https://attack.mitre.org/tactics/TA0001/

Framework: MITRE ATT&CK

• Tactic:
  • Name: Execution
  • Id: TA0002
  • Reference URL: https://attack.mitre.org/tactics/TA0002/

Framework: MITRE ATT&CK

• Tactic:
  • Name: Defense Evasion
  • Id: TA0005
  • Reference URL: https://attack.mitre.org/tactics/TA0005/