NRT Azure Active Directory Hybrid Health AD FS New Server

AzureActivity
| where CategoryValue =~ 'Administrative'
| where ResourceProviderValue =~ 'Microsoft.ADHybridHealthService'
| where _ResourceId has 'AdFederationService'
| where OperationNameValue =~ 'Microsoft.ADHybridHealthService/services/servicemembers/action'
| extend claimsJson = parse_json(Claims)
| extend AppId = tostring(claimsJson.appid), AccountName = tostring(claimsJson.name), Name = tostring(split(Caller,'@',0)[0]), UPNSuffix = tostring(split(Caller,'@',1)[0])
| project-away claimsJson

severity: Medium
description: |
  'This detection uses AzureActivity logs (Administrative category) to identify the creation or update of a server instance in an Azure AD Hybrid Health AD FS service.
  A threat actor can create a new AD Health ADFS service and create a fake server instance to spoof AD FS signing logs. There is no need to compromise an on-premises AD FS server.
  This can be done programmatically via HTTP requests to Azure. More information in this blog: https://o365blog.com/post/hybridhealthagent/'  
tags:
- SimuLand
relevantTechniques:
- T1578
kind: NRT
requiredDataConnectors:
- dataTypes:
  - AzureActivity
  connectorId: AzureActivity
tactics:
- DefenseEvasion
query: |
  AzureActivity
  | where CategoryValue =~ 'Administrative'
  | where ResourceProviderValue =~ 'Microsoft.ADHybridHealthService'
  | where _ResourceId has 'AdFederationService'
  | where OperationNameValue =~ 'Microsoft.ADHybridHealthService/services/servicemembers/action'
  | extend claimsJson = parse_json(Claims)
  | extend AppId = tostring(claimsJson.appid), AccountName = tostring(claimsJson.name), Name = tostring(split(Caller,'@',0)[0]), UPNSuffix = tostring(split(Caller,'@',1)[0])
  | project-away claimsJson  
status: Available
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Azure Activity/Analytic Rules/NRT-AADHybridHealthADFSNewServer.yaml
version: 2.0.1
id: ec491363-5fe7-4eff-b68e-f42dcb76fcf6
entityMappings:
- fieldMappings:
  - columnName: Name
    identifier: Name
  - columnName: UPNSuffix
    identifier: UPNSuffix
  entityType: Account
- fieldMappings:
  - columnName: CallerIpAddress
    identifier: Address
  entityType: IP
name: NRT Azure Active Directory Hybrid Health AD FS New Server

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/ec491363-5fe7-4eff-b68e-f42dcb76fcf6')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/ec491363-5fe7-4eff-b68e-f42dcb76fcf6')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "NRT",
      "apiVersion": "2022-11-01-preview",
      "properties": {
        "displayName": "NRT Azure Active Directory Hybrid Health AD FS New Server",
        "description": "'This detection uses AzureActivity logs (Administrative category) to identify the creation or update of a server instance in an Azure AD Hybrid Health AD FS service.\nA threat actor can create a new AD Health ADFS service and create a fake server instance to spoof AD FS signing logs. There is no need to compromise an on-premises AD FS server.\nThis can be done programmatically via HTTP requests to Azure. More information in this blog: https://o365blog.com/post/hybridhealthagent/'\n",
        "severity": "Medium",
        "enabled": true,
        "query": "AzureActivity\n| where CategoryValue =~ 'Administrative'\n| where ResourceProviderValue =~ 'Microsoft.ADHybridHealthService'\n| where _ResourceId has 'AdFederationService'\n| where OperationNameValue =~ 'Microsoft.ADHybridHealthService/services/servicemembers/action'\n| extend claimsJson = parse_json(Claims)\n| extend AppId = tostring(claimsJson.appid), AccountName = tostring(claimsJson.name), Name = tostring(split(Caller,'@',0)[0]), UPNSuffix = tostring(split(Caller,'@',1)[0])\n| project-away claimsJson\n",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "techniques": [
          "T1578"
        ],
        "alertRuleTemplateName": "ec491363-5fe7-4eff-b68e-f42dcb76fcf6",
        "customDetails": null,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "Name",
                "identifier": "Name"
              },
              {
                "columnName": "UPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "CallerIpAddress",
                "identifier": "Address"
              }
            ]
          }
        ],
        "tags": [
          "SimuLand"
        ],
        "status": "Available",
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Azure Activity/Analytic Rules/NRT-AADHybridHealthADFSNewServer.yaml",
        "templateVersion": "2.0.1"
      }
    }
  ]
}