Microsoft Entra ID Health Service Agents Registry Keys Access

// ADHealth Monitoring Agent Registry Key
let aadHealthMonAgentRegKey = "\\REGISTRY\\MACHINE\\SOFTWARE\\Microsoft\\MicrosoftOnline\\Reporting\\MonitoringAgent";
// Filter out known processes
let aadConnectHealthProcs = dynamic ([
    'Microsoft.Identity.Health.Adfs.DiagnosticsAgent.exe',
    'Microsoft.Identity.Health.Adfs.InsightsService.exe',
    'Microsoft.Identity.Health.Adfs.MonitoringAgent.Startup.exe',
    'Microsoft.Identity.Health.Adfs.PshSurrogate.exe',
    'Microsoft.Identity.Health.Common.Clients.ResourceMonitor.exe',
    'Microsoft.Identity.Health.AadSync.MonitoringAgent.Startup.exe',
    'Microsoft.Identity.AadConnect.Health.AadSync.Host.exe',
    'Microsoft.Azure.ActiveDirectory.Synchronization.Upgrader.exe',
    'miiserver.exe'
]);
(union isfuzzy=true
(
SecurityEvent
| where EventID == '4656'
| where EventData has aadHealthMonAgentRegKey
| extend EventData = parse_xml(EventData).EventData.Data
| mv-expand bagexpansion=array EventData
| evaluate bag_unpack(EventData)
| extend Key = tostring(column_ifexists('@Name', "")), Value = column_ifexists('#text', "")
| evaluate pivot(Key, any(Value), TimeGenerated, Computer, EventID)
| extend ObjectName = column_ifexists("ObjectName", ""),
    ObjectType = column_ifexists("ObjectType", "")
| where ObjectType == 'Key'
| where ObjectName == aadHealthMonAgentRegKey
| extend SubjectUserName = column_ifexists("SubjectUserName", ""),
    SubjectDomainName = column_ifexists("SubjectDomainName", ""),
    ProcessName = column_ifexists("ProcessName", "")
| extend Process = split(ProcessName, '\\', -1)[-1],
    Account = strcat(SubjectDomainName, "\\", SubjectUserName)
| where Process !in (aadConnectHealthProcs)
| summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName
),
  ( WindowsEvent
| where EventID == '4656' and EventData has aadHealthMonAgentRegKey
| extend ObjectType = tostring(EventData.ObjectType)
| where ObjectType == 'Key'
| extend ObjectName = tostring(EventData.ObjectName)
| where ObjectName == aadHealthMonAgentRegKey
| extend ProcessName = tostring(EventData.ProcessName)
| extend Process = tostring(split(ProcessName, '\\')[-1])
| where Process !in (aadConnectHealthProcs)
| extend Account =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
| extend SubjectUserName = tostring(EventData.SubjectUserName)
| extend SubjectDomainName = tostring(EventData.SubjectDomainName)
| summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName
),
(
SecurityEvent
| where EventID == '4663'
| where ObjectType == 'Key'
| where ObjectName == aadHealthMonAgentRegKey
| extend Process = tostring(split(ProcessName, '\\', -1)[-1])
| where Process !in (aadConnectHealthProcs)
| summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName
),
( WindowsEvent
| where EventID == '4663' and EventData has aadHealthMonAgentRegKey
| extend ObjectType = tostring(EventData.ObjectType)
| where ObjectType == 'Key'
| extend ObjectName = tostring(EventData.ObjectName)
| where ObjectName == aadHealthMonAgentRegKey
| extend ProcessName = tostring(EventData.ProcessName)
| extend Process = tostring(split(ProcessName, '\\')[-1])
| where Process !in (aadConnectHealthProcs)
| extend Account =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
| extend SubjectUserName = tostring(EventData.SubjectUserName)
| extend SubjectDomainName = tostring(EventData.SubjectDomainName)
| summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName
)
)
// You can filter out potential machine accounts
//| where AccountType != 'Machine'
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| extend Name = tostring(split(Account, "\\")[1]), NTDomain = tostring(split(Account, "\\")[0])

relevantTechniques:
- T1005
name: Microsoft Entra ID Health Service Agents Registry Keys Access
requiredDataConnectors:
- dataTypes:
  - SecurityEvent
  connectorId: SecurityEvents
- dataTypes:
  - SecurityEvents
  connectorId: WindowsSecurityEvents
- dataTypes:
  - WindowsEvent
  connectorId: WindowsForwardedEvents
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: Account
  - identifier: Name
    columnName: Name
  - identifier: NTDomain
    columnName: NTDomain
  entityType: Account
- fieldMappings:
  - identifier: FullName
    columnName: Computer
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: HostNameDomain
  entityType: Host
triggerThreshold: 0
id: 06bbf969-fcbe-43fa-bac2-b2fa131d113a
tactics:
- Collection
version: 1.1.5
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/AADHealthSvcAgentRegKeyAccess.yaml
queryPeriod: 1d
kind: Scheduled
tags:
- SimuLand
metadata:
  categories:
    domains:
    - Security - Others
    - Identity
  author:
    name: Microsoft Security Research
  support:
    tier: Community
  source:
    kind: Community
queryFrequency: 1d
severity: Medium
description: |
  'This detection uses Windows security events to detect suspicious access attempts to the registry key values and sub-keys of Microsoft Entra ID Health service agents (e.g AD FS).
  Information from AD Health service agents can be used to potentially abuse some of the features provided by those services in the cloud (e.g. Federation).
  This detection requires an access control entry (ACE) on the system access control list (SACL) of the following securable object: HKLM:\SOFTWARE\Microsoft\ADHealthAgent.
  Make sure you set the SACL to propagate to its sub-keys. You can find more information in here https://github.com/OTRF/Set-AuditRule/blob/master/rules/registry/aad_connect_health_service_agent.yml
  '  
query: |
  // ADHealth Monitoring Agent Registry Key
  let aadHealthMonAgentRegKey = "\\REGISTRY\\MACHINE\\SOFTWARE\\Microsoft\\MicrosoftOnline\\Reporting\\MonitoringAgent";
  // Filter out known processes
  let aadConnectHealthProcs = dynamic ([
      'Microsoft.Identity.Health.Adfs.DiagnosticsAgent.exe',
      'Microsoft.Identity.Health.Adfs.InsightsService.exe',
      'Microsoft.Identity.Health.Adfs.MonitoringAgent.Startup.exe',
      'Microsoft.Identity.Health.Adfs.PshSurrogate.exe',
      'Microsoft.Identity.Health.Common.Clients.ResourceMonitor.exe',
      'Microsoft.Identity.Health.AadSync.MonitoringAgent.Startup.exe',
      'Microsoft.Identity.AadConnect.Health.AadSync.Host.exe',
      'Microsoft.Azure.ActiveDirectory.Synchronization.Upgrader.exe',
      'miiserver.exe'
  ]);
  (union isfuzzy=true
  (
  SecurityEvent
  | where EventID == '4656'
  | where EventData has aadHealthMonAgentRegKey
  | extend EventData = parse_xml(EventData).EventData.Data
  | mv-expand bagexpansion=array EventData
  | evaluate bag_unpack(EventData)
  | extend Key = tostring(column_ifexists('@Name', "")), Value = column_ifexists('#text', "")
  | evaluate pivot(Key, any(Value), TimeGenerated, Computer, EventID)
  | extend ObjectName = column_ifexists("ObjectName", ""),
      ObjectType = column_ifexists("ObjectType", "")
  | where ObjectType == 'Key'
  | where ObjectName == aadHealthMonAgentRegKey
  | extend SubjectUserName = column_ifexists("SubjectUserName", ""),
      SubjectDomainName = column_ifexists("SubjectDomainName", ""),
      ProcessName = column_ifexists("ProcessName", "")
  | extend Process = split(ProcessName, '\\', -1)[-1],
      Account = strcat(SubjectDomainName, "\\", SubjectUserName)
  | where Process !in (aadConnectHealthProcs)
  | summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName
  ),
    ( WindowsEvent
  | where EventID == '4656' and EventData has aadHealthMonAgentRegKey
  | extend ObjectType = tostring(EventData.ObjectType)
  | where ObjectType == 'Key'
  | extend ObjectName = tostring(EventData.ObjectName)
  | where ObjectName == aadHealthMonAgentRegKey
  | extend ProcessName = tostring(EventData.ProcessName)
  | extend Process = tostring(split(ProcessName, '\\')[-1])
  | where Process !in (aadConnectHealthProcs)
  | extend Account =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
  | extend SubjectUserName = tostring(EventData.SubjectUserName)
  | extend SubjectDomainName = tostring(EventData.SubjectDomainName)
  | summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName
  ),
  (
  SecurityEvent
  | where EventID == '4663'
  | where ObjectType == 'Key'
  | where ObjectName == aadHealthMonAgentRegKey
  | extend Process = tostring(split(ProcessName, '\\', -1)[-1])
  | where Process !in (aadConnectHealthProcs)
  | summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName
  ),
  ( WindowsEvent
  | where EventID == '4663' and EventData has aadHealthMonAgentRegKey
  | extend ObjectType = tostring(EventData.ObjectType)
  | where ObjectType == 'Key'
  | extend ObjectName = tostring(EventData.ObjectName)
  | where ObjectName == aadHealthMonAgentRegKey
  | extend ProcessName = tostring(EventData.ProcessName)
  | extend Process = tostring(split(ProcessName, '\\')[-1])
  | where Process !in (aadConnectHealthProcs)
  | extend Account =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
  | extend SubjectUserName = tostring(EventData.SubjectUserName)
  | extend SubjectDomainName = tostring(EventData.SubjectDomainName)
  | summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName
  )
  )
  // You can filter out potential machine accounts
  //| where AccountType != 'Machine'
  | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
  | extend Name = tostring(split(Account, "\\")[1]), NTDomain = tostring(split(Account, "\\")[0])  
triggerOperator: gt

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/06bbf969-fcbe-43fa-bac2-b2fa131d113a')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/06bbf969-fcbe-43fa-bac2-b2fa131d113a')]",
      "properties": {
        "alertRuleTemplateName": "06bbf969-fcbe-43fa-bac2-b2fa131d113a",
        "customDetails": null,
        "description": "'This detection uses Windows security events to detect suspicious access attempts to the registry key values and sub-keys of Microsoft Entra ID Health service agents (e.g AD FS).\nInformation from AD Health service agents can be used to potentially abuse some of the features provided by those services in the cloud (e.g. Federation).\nThis detection requires an access control entry (ACE) on the system access control list (SACL) of the following securable object: HKLM:\\SOFTWARE\\Microsoft\\ADHealthAgent.\nMake sure you set the SACL to propagate to its sub-keys. You can find more information in here https://github.com/OTRF/Set-AuditRule/blob/master/rules/registry/aad_connect_health_service_agent.yml\n'\n",
        "displayName": "Microsoft Entra ID Health Service Agents Registry Keys Access",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "Account",
                "identifier": "FullName"
              },
              {
                "columnName": "Name",
                "identifier": "Name"
              },
              {
                "columnName": "NTDomain",
                "identifier": "NTDomain"
              }
            ]
          },
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "Computer",
                "identifier": "FullName"
              },
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "HostNameDomain",
                "identifier": "DnsDomain"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/AADHealthSvcAgentRegKeyAccess.yaml",
        "query": "// ADHealth Monitoring Agent Registry Key\nlet aadHealthMonAgentRegKey = \"\\\\REGISTRY\\\\MACHINE\\\\SOFTWARE\\\\Microsoft\\\\MicrosoftOnline\\\\Reporting\\\\MonitoringAgent\";\n// Filter out known processes\nlet aadConnectHealthProcs = dynamic ([\n    'Microsoft.Identity.Health.Adfs.DiagnosticsAgent.exe',\n    'Microsoft.Identity.Health.Adfs.InsightsService.exe',\n    'Microsoft.Identity.Health.Adfs.MonitoringAgent.Startup.exe',\n    'Microsoft.Identity.Health.Adfs.PshSurrogate.exe',\n    'Microsoft.Identity.Health.Common.Clients.ResourceMonitor.exe',\n    'Microsoft.Identity.Health.AadSync.MonitoringAgent.Startup.exe',\n    'Microsoft.Identity.AadConnect.Health.AadSync.Host.exe',\n    'Microsoft.Azure.ActiveDirectory.Synchronization.Upgrader.exe',\n    'miiserver.exe'\n]);\n(union isfuzzy=true\n(\nSecurityEvent\n| where EventID == '4656'\n| where EventData has aadHealthMonAgentRegKey\n| extend EventData = parse_xml(EventData).EventData.Data\n| mv-expand bagexpansion=array EventData\n| evaluate bag_unpack(EventData)\n| extend Key = tostring(column_ifexists('@Name', \"\")), Value = column_ifexists('#text', \"\")\n| evaluate pivot(Key, any(Value), TimeGenerated, Computer, EventID)\n| extend ObjectName = column_ifexists(\"ObjectName\", \"\"),\n    ObjectType = column_ifexists(\"ObjectType\", \"\")\n| where ObjectType == 'Key'\n| where ObjectName == aadHealthMonAgentRegKey\n| extend SubjectUserName = column_ifexists(\"SubjectUserName\", \"\"),\n    SubjectDomainName = column_ifexists(\"SubjectDomainName\", \"\"),\n    ProcessName = column_ifexists(\"ProcessName\", \"\")\n| extend Process = split(ProcessName, '\\\\', -1)[-1],\n    Account = strcat(SubjectDomainName, \"\\\\\", SubjectUserName)\n| where Process !in (aadConnectHealthProcs)\n| summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName\n),\n  ( WindowsEvent\n| where EventID == '4656' and EventData has aadHealthMonAgentRegKey\n| extend ObjectType = tostring(EventData.ObjectType)\n| where ObjectType == 'Key'\n| extend ObjectName = tostring(EventData.ObjectName)\n| where ObjectName == aadHealthMonAgentRegKey\n| extend ProcessName = tostring(EventData.ProcessName)\n| extend Process = tostring(split(ProcessName, '\\\\')[-1])\n| where Process !in (aadConnectHealthProcs)\n| extend Account =  strcat(tostring(EventData.SubjectDomainName),\"\\\\\", tostring(EventData.SubjectUserName))\n| extend SubjectUserName = tostring(EventData.SubjectUserName)\n| extend SubjectDomainName = tostring(EventData.SubjectDomainName)\n| summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName\n),\n(\nSecurityEvent\n| where EventID == '4663'\n| where ObjectType == 'Key'\n| where ObjectName == aadHealthMonAgentRegKey\n| extend Process = tostring(split(ProcessName, '\\\\', -1)[-1])\n| where Process !in (aadConnectHealthProcs)\n| summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName\n),\n( WindowsEvent\n| where EventID == '4663' and EventData has aadHealthMonAgentRegKey\n| extend ObjectType = tostring(EventData.ObjectType)\n| where ObjectType == 'Key'\n| extend ObjectName = tostring(EventData.ObjectName)\n| where ObjectName == aadHealthMonAgentRegKey\n| extend ProcessName = tostring(EventData.ProcessName)\n| extend Process = tostring(split(ProcessName, '\\\\')[-1])\n| where Process !in (aadConnectHealthProcs)\n| extend Account =  strcat(tostring(EventData.SubjectDomainName),\"\\\\\", tostring(EventData.SubjectUserName))\n| extend SubjectUserName = tostring(EventData.SubjectUserName)\n| extend SubjectDomainName = tostring(EventData.SubjectDomainName)\n| summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName\n)\n)\n// You can filter out potential machine accounts\n//| where AccountType != 'Machine'\n| extend HostName = tostring(split(Computer, \".\")[0]), DomainIndex = toint(indexof(Computer, '.'))\n| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)\n| extend Name = tostring(split(Account, \"\\\\\")[1]), NTDomain = tostring(split(Account, \"\\\\\")[0])\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Collection"
        ],
        "tags": [
          "SimuLand"
        ],
        "techniques": [
          "T1005"
        ],
        "templateVersion": "1.1.5",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}