ATP policy status check

Hunt Hypothesis

Adversaries may disable or bypass Safe Attachments and Safe Documents policies to exfiltrate malicious files through SharePoint, OneDrive, or Teams. SOC teams should proactively hunt for this behavior to identify potential exfiltration attempts and prevent data loss in their Azure Sentinel environment.

KQL Query

CloudAppEvents
| where Application == "Microsoft Exchange Online"
| where ActionType == "Set-AtpPolicyForO365"
| mv-expand ActivityObjects
| extend Name = tostring(ActivityObjects.Name)
| extend Value = tostring(ActivityObjects.Value)
| where Name in ("EnableATPForSPOTeamsODB", "EnableSafeDocs", "AllowSafeDocsOpen")
| extend packed = pack(Name, Value)
| summarize PackedInfo = make_bag(packed), ActionType = any(ActionType) by Timestamp, AccountDisplayName
| evaluate bag_unpack(PackedInfo)

Analytic Rule Definition

id: 518e6938-10ef-4165-af19-82f1287141bc
name: ATP policy status check
description: |
  This query displays the configuration auditing for 'Safe Attachments for SharePoint, OneDrive, and Microsoft Teams' and 'Safe Documents' in Microsoft Defender for Office 365.
description-detailed: |
  This query displays the configuration auditing for 'Safe Attachments for SharePoint, OneDrive, and Microsoft Teams' and 'Safe Documents' settings in Microsoft Defender for Office 365.
  Reference - https://learn.microsoft.com/en-us/defender-office-365/safe-attachments-about
requiredDataConnectors:
  - connectorId: MicrosoftThreatProtection
    dataTypes:
      - CloudAppEvents
tactics:
  - DefenseEvasion
relevantTechniques:
  - T1562
query: |
  CloudAppEvents
  | where Application == "Microsoft Exchange Online"
  | where ActionType == "Set-AtpPolicyForO365"
  | mv-expand ActivityObjects
  | extend Name = tostring(ActivityObjects.Name)
  | extend Value = tostring(ActivityObjects.Value)
  | where Name in ("EnableATPForSPOTeamsODB", "EnableSafeDocs", "AllowSafeDocsOpen")
  | extend packed = pack(Name, Value)
  | summarize PackedInfo = make_bag(packed), ActionType = any(ActionType) by Timestamp, AccountDisplayName
  | evaluate bag_unpack(PackedInfo)
version: 1.0.0

Required Data Sources

MITRE ATT&CK Context

• Tactic: DefenseEvasion
• Technique: T1562 — T1562

References

• [Source Query](https://github.com/Azure/Azure-Sentinel/blob/main/Hunting Queries/Microsoft 365 Defender/Email and Collaboration Queries/Attachment/ATP policy status check.yaml)

False Positive Guidance

• Scenario: Scheduled Compliance Audit Job
  Description: A scheduled job runs to audit ATP (Advanced Threat Protection) policies as part of routine compliance checks.
  Filter/Exclusion: where AuditJobName contains "Compliance Audit" or AuditJobName contains "Scheduled Audit"

• Scenario: Admin Manual Policy Review
  Description: An admin manually reviews the ATP policy configuration using the Microsoft 365 Compliance Center or the Microsoft Defender for Office 365 admin center.
  Filter/Exclusion: where UserEmail contains "[email protected]" or UserEmail contains "[email protected]"

• Scenario: Policy Sync Between Tenants
  Description: A cross-tenant policy synchronization task triggers a configuration audit when policies are being synced between Microsoft 365 tenants.
  Filter/Exclusion: where SourceTenantId != TargetTenantId or ActivityType contains "Tenant Sync"

• Scenario: Automated Policy Update via PowerShell
  Description: A PowerShell script or automation tool updates ATP policies across multiple environments, which may trigger configuration audit events.
  Filter/Exclusion: where ProcessName contains "powershell.exe" or ScriptName contains "Update-ATPPolicy.ps1"

• Scenario: Third-Party Tool Integration
  Description: A third-party security tool or SIEM integration periodically checks ATP policy status for correlation with other security data.
  Filter/Exclusion: where SourceSystem contains "SIEM" or SourceSystem contains "ThirdPartyTool"