Azure Diagnostic settings removed from a resource

id: 6e95aef3-a1e0-4063-8e74-cd59aa59f245
name: Azure Diagnostic settings removed from a resource
description: |
  'This query looks for diagnostic settings that are removed from a resource.
  This could indicate an attacker or malicious internal trying to evade detection before malicious act is performed.
  If the diagnostic settings are being deleted as part of a parent resource deletion, the event is ignores.'
severity: Medium
requiredDataConnectors:
  - connectorId: AzureActivity
    dataTypes:
      - AzureActivity
queryFrequency: 1h
queryPeriod: 2h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - DefenseEvasion
relevantTechniques:
  - T1562.008
query: |
  AzureActivity
  | where OperationNameValue =~ "MICROSOFT.INSIGHTS/DIAGNOSTICSETTINGS/DELETE"
  | summarize
      TimeGenerated = arg_max(TimeGenerated, Properties),
      ActivityStatusValue = make_set(ActivityStatusValue, 5),
      take_any(Caller, CallerIpAddress, OperationName, ResourceGroup, Resource)
      by CorrelationId, _ResourceId, OperationNameValue
  | extend ResourceHierarchy = split(_ResourceId, "/")
  | extend MonitoredResourcePath = strcat_array(array_slice(ResourceHierarchy, 0, array_length(ResourceHierarchy)-5), "/")
  | join kind=leftanti (
      AzureActivity
      | where OperationNameValue !~ "MICROSOFT.INSIGHTS/DIAGNOSTICSETTINGS/DELETE" and OperationNameValue endswith "/DELETE" and ActivityStatusValue has_any ("Success", "Succeeded")
      | project _ResourceId
  ) on $left.MonitoredResourcePath == $right._ResourceId
  | extend
      Name = iif(Caller has "@", tostring(split(Caller, "@")[0]), ""),
      UPNSuffix = iif(Caller has "@", tostring(split(Caller, "@")[1]), ""),
      AadUserId = iif(Caller has "@", "", Caller)
  | project TimeGenerated, Caller, CallerIpAddress, OperationNameValue, OperationName, ActivityStatusValue, ResourceGroup, MonitoredResourcePath, Resource, Properties, Name, UPNSuffix, AadUserId, _ResourceId, CorrelationId
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: Caller
      - identifier: Name
        columnName: Name
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: Account
    fieldMappings:
      - identifier: AadUserId
        columnName: AadUserId
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: CallerIpAddress
version: 1.0.3
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: KennethMLdk
    support:
        tier: Community
    categories:
        domains: [ "Security - Others", "Platform" ]