Azure AD Health Service Agents Registry Keys Access

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Id	06bbf969-fcbe-43fa-bac2-b2fa131d113a
Rulename	Azure AD Health Service Agents Registry Keys Access
Description	This detection uses Windows security events to detect suspicious access attempts to the registry key values and sub-keys of Azure AD 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
Severity	Medium
Tactics	Collection
Techniques	T1005
Required data connectors	SecurityEvents WindowsForwardedEvents WindowsSecurityEvents
Kind	Scheduled
Query frequency	1d
Query period	1d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/AADHealthSvcAgentRegKeyAccess.yaml
Version	1.1.2
Arm template	06bbf969-fcbe-43fa-bac2-b2fa131d113a.json

KQL

// 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 timestamp = StartTime, AccountCustomEntity = Account, HostCustomEntity = Computer

YAML

requiredDataConnectors:
- connectorId: SecurityEvents
  dataTypes:
  - SecurityEvent
- connectorId: WindowsSecurityEvents
  dataTypes:
  - SecurityEvents
- connectorId: WindowsForwardedEvents
  dataTypes:
  - WindowsEvent
triggerOperator: gt
queryFrequency: 1d
name: Azure AD Health Service Agents Registry Keys Access
tags:
- SimuLand
queryPeriod: 1d
metadata:
  categories:
    domains:
    - Security - Others
    - Identity
  support:
    tier: Community
  author:
    name: Roberto Rodriguez
  source:
    kind: Community
id: 06bbf969-fcbe-43fa-bac2-b2fa131d113a
description: |
  'This detection uses Windows security events to detect suspicious access attempts to the registry key values and sub-keys of Azure AD 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
  '  
severity: Medium
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 timestamp = StartTime, AccountCustomEntity = Account, HostCustomEntity = Computer  
version: 1.1.2
kind: Scheduled
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/AADHealthSvcAgentRegKeyAccess.yaml
entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: AccountCustomEntity
- entityType: Host
  fieldMappings:
  - identifier: FullName
    columnName: HostCustomEntity
relevantTechniques:
- T1005
tactics:
- Collection
triggerThreshold: 0

ARM

{
  "$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/06bbf969-fcbe-43fa-bac2-b2fa131d113a')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/06bbf969-fcbe-43fa-bac2-b2fa131d113a')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01-preview",
      "properties": {
        "displayName": "Azure AD Health Service Agents Registry Keys Access",
        "description": "'This detection uses Windows security events to detect suspicious access attempts to the registry key values and sub-keys of Azure AD 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",
        "severity": "Medium",
        "enabled": true,
        "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 timestamp = StartTime, AccountCustomEntity = Account, HostCustomEntity = Computer\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Collection"
        ],
        "techniques": [
          "T1005"
        ],
        "alertRuleTemplateName": "06bbf969-fcbe-43fa-bac2-b2fa131d113a",
        "customDetails": null,
        "entityMappings": [
          {
            "fieldMappings": [
              {
                "identifier": "FullName",
                "columnName": "AccountCustomEntity"
              }
            ],
            "entityType": "Account"
          },
          {
            "fieldMappings": [
              {
                "identifier": "FullName",
                "columnName": "HostCustomEntity"
              }
            ],
            "entityType": "Host"
          }
        ],
        "tags": [
          "SimuLand"
        ],
        "templateVersion": "1.1.2",
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/AADHealthSvcAgentRegKeyAccess.yaml"
      }
    }
  ]
}