Azure Diagnostic settings removed from a resource

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Id	6e95aef3-a1e0-4063-8e74-cd59aa59f245
Rulename	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
Tactics	DefenseEvasion
Techniques	T1562.008
Required data connectors	AzureActivity
Kind	Scheduled
Query frequency	1h
Query period	2h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AzureActivity/AzDiagSettingsDeleted.yaml
Version	1.0.3
Arm template	6e95aef3-a1e0-4063-8e74-cd59aa59f245.json

KQL

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

YAML

name: Azure Diagnostic settings removed from a resource
id: 6e95aef3-a1e0-4063-8e74-cd59aa59f245
triggerThreshold: 0
severity: Medium
tactics:
- DefenseEvasion
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AzureActivity/AzDiagSettingsDeleted.yaml
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: Caller
    identifier: FullName
  - columnName: Name
    identifier: Name
  - columnName: UPNSuffix
    identifier: UPNSuffix
- entityType: Account
  fieldMappings:
  - columnName: AadUserId
    identifier: AadUserId
- entityType: IP
  fieldMappings:
  - columnName: CallerIpAddress
    identifier: Address
queryPeriod: 2h
queryFrequency: 1h
version: 1.0.3
triggerOperator: gt
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.'  
metadata:
  support:
    tier: Community
  author:
    name: KennethMLdk
  source:
    kind: Community
  categories:
    domains:
    - Security - Others
    - Platform
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  
relevantTechniques:
- T1562.008
requiredDataConnectors:
- dataTypes:
  - AzureActivity
  connectorId: AzureActivity
kind: Scheduled

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2023-02-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/6e95aef3-a1e0-4063-8e74-cd59aa59f245')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/6e95aef3-a1e0-4063-8e74-cd59aa59f245')]",
      "properties": {
        "alertRuleTemplateName": "6e95aef3-a1e0-4063-8e74-cd59aa59f245",
        "customDetails": null,
        "description": "'This query looks for diagnostic settings that are removed from a resource.\nThis could indicate an attacker or malicious internal trying to evade detection before malicious act is performed.\nIf the diagnostic settings are being deleted as part of a parent resource deletion, the event is ignores.'\n",
        "displayName": "Azure Diagnostic settings removed from a resource",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "Caller",
                "identifier": "FullName"
              },
              {
                "columnName": "Name",
                "identifier": "Name"
              },
              {
                "columnName": "UPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "AadUserId",
                "identifier": "AadUserId"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "CallerIpAddress",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AzureActivity/AzDiagSettingsDeleted.yaml",
        "query": "AzureActivity\n| where OperationNameValue =~ \"MICROSOFT.INSIGHTS/DIAGNOSTICSETTINGS/DELETE\"\n| summarize\n    TimeGenerated = arg_max(TimeGenerated, Properties),\n    ActivityStatusValue = make_set(ActivityStatusValue, 5),\n    take_any(Caller, CallerIpAddress, OperationName, ResourceGroup, Resource)\n    by CorrelationId, _ResourceId, OperationNameValue\n| extend ResourceHierarchy = split(_ResourceId, \"/\")\n| extend MonitoredResourcePath = strcat_array(array_slice(ResourceHierarchy, 0, array_length(ResourceHierarchy)-5), \"/\")\n| join kind=leftanti (\n    AzureActivity\n    | where OperationNameValue !~ \"MICROSOFT.INSIGHTS/DIAGNOSTICSETTINGS/DELETE\" and OperationNameValue endswith \"/DELETE\" and ActivityStatusValue has_any (\"Success\", \"Succeeded\")\n    | project _ResourceId\n) on $left.MonitoredResourcePath == $right._ResourceId\n| extend\n    Name = iif(Caller has \"@\", tostring(split(Caller, \"@\")[0]), \"\"),\n    UPNSuffix = iif(Caller has \"@\", tostring(split(Caller, \"@\")[1]), \"\"),\n    AadUserId = iif(Caller has \"@\", \"\", Caller)\n| project TimeGenerated, Caller, CallerIpAddress, OperationNameValue, OperationName, ActivityStatusValue, ResourceGroup, MonitoredResourcePath, Resource, Properties, Name, UPNSuffix, AadUserId, _ResourceId, CorrelationId\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT2H",
        "severity": "Medium",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "techniques": [
          "T1562"
        ],
        "templateVersion": "1.0.3",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}