Microsoft Entra ID Health Monitoring Agent Registry Keys Access

Severity: medium
Time window: 1d
Group by: Account, Computer, EventID, ObjectName, ObjectType, Process, ProcessName, SubjectDomainName, SubjectUserName
Author: Microsoft Security Research
Source: github.com/Azure/Azure-Sentinel

This detection uses Windows security events to detect suspicious access attempts to the registry key of Microsoft Entra ID Health monitoring agent. This detection requires an access control entry (ACE) on the system access control list (SACL) of the following securable object HKLM\SOFTWARE\Microsoft\Microsoft Online\Reporting\MonitoringAgent. You can find more information in here https://github.com/OTRF/Set-AuditRule/blob/master/rules/registry/aad_connect_health_monitoring_agent.yml

MITRE ATT&CK coverage

Tactic	Techniques
Collection	`T1005` Data from Local System

Event coverage

Provider	Event	Title
Security-Auditing	Event ID 4656	A handle to an object was requested.
Security-Auditing	Event ID 4663	An attempt was made to access an object.

Rule body kusto

id: f819c592-c5f9-4d5c-a79f-1e6819863533
name: Microsoft Entra ID Health Monitoring Agent Registry Keys Access
description: |
  'This detection uses Windows security events to detect suspicious access attempts to the registry key of Microsoft Entra ID Health monitoring agent.
  This detection requires an access control entry (ACE) on the system access control list (SACL) of the following securable object HKLM\SOFTWARE\Microsoft\Microsoft Online\Reporting\MonitoringAgent.
  You can find more information in here https://github.com/OTRF/Set-AuditRule/blob/master/rules/registry/aad_connect_health_monitoring_agent.yml
  '
severity: Medium
requiredDataConnectors:
  - connectorId: SecurityEvents
    dataTypes:
      - SecurityEvent
  - connectorId: WindowsSecurityEvents
    dataTypes: 
      - SecurityEvents 
  - connectorId: WindowsForwardedEvents
    dataTypes: 
      - WindowsEvent 
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Collection
relevantTechniques:
  - T1005
tags:
  - SimuLand
query: |
  // ADHealth Monitoring Agent Registry Key
  let aadHealthMonAgentRegKey = "\\REGISTRY\\MACHINE\\SOFTWARE\\Microsoft\\Microsoft Online\\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])
  | project-away DomainIndex
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: Account
      - identifier: Name
        columnName: Name
      - identifier: NTDomain
        columnName: NTDomain
  - entityType: Host
    fieldMappings:
      - identifier: FullName
        columnName: Computer
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: HostNameDomain
version: 1.1.6
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Microsoft Security Research
    support:
        tier: Community
    categories:
        domains: [ "Security - Others", "Identity" ]

Stages and Predicates

Stage 0: `let`

let aadHealthMonAgentRegKey = "\\REGISTRY\\MACHINE\\SOFTWARE\\Microsoft\\Microsoft Online\\Reporting\\MonitoringAgent";
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'
]);

Stage 1: `union`

union isfuzzy=true

Stage 2: `source` time_window=86400s

SecurityEvent

Stage 3: `where`

| where EventID == '4656'

Stage 4: `where`

| where EventData has aadHealthMonAgentRegKey

Stage 5: `extend`

| extend EventData = parse_xml(EventData).EventData.Data

Stage 6: `mv-expand`

| mv-expand bagexpansion=array EventData

Stage 7: `evaluate`

| evaluate bag_unpack(EventData)

Stage 8: `extend`

| extend Key = tostring(column_ifexists('@Name', "")), Value = column_ifexists('#text', "")

Stage 9: `evaluate`

| evaluate pivot(Key, any(Value), TimeGenerated, Computer, EventID)

Stage 10: `extend`

| extend ObjectName = column_ifexists("ObjectName", ""),
    ObjectType = column_ifexists("ObjectType", "")

Stage 11: `where`

| where ObjectType == 'Key'

Stage 12: `where`

| where ObjectName == aadHealthMonAgentRegKey

Stage 13: `extend`

| extend SubjectUserName = column_ifexists("SubjectUserName", ""),
    SubjectDomainName = column_ifexists("SubjectDomainName", ""),
    ProcessName = column_ifexists("ProcessName", "")

Stage 14: `extend`

| extend Process = split(ProcessName, '\\', -1)[-1],
    Account = strcat(SubjectDomainName, "\\", SubjectUserName)

Stage 15: `where`

| where Process !in (aadConnectHealthProcs)

Stage 16: `summarize`

| summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName

Stage 17: `source`

WindowsEvent

Stage 18: `where`

| where EventID == '4656' and EventData has aadHealthMonAgentRegKey

Stage 19: `extend`

| extend ObjectType = tostring(EventData.ObjectType)

Stage 20: `where`

| where ObjectType == 'Key'

Stage 21: `extend`

| extend ObjectName = tostring(EventData.ObjectName)

Stage 22: `where`

| where ObjectName == aadHealthMonAgentRegKey

Stage 23: `extend`

| extend ProcessName = tostring(EventData.ProcessName)

Stage 24: `extend`

| extend Process = tostring(split(ProcessName, '\\')[-1])

Stage 25: `where`

| where Process !in (aadConnectHealthProcs)

Stage 26: `extend`

| extend Account =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))

Stage 27: `extend`

| extend SubjectUserName = tostring(EventData.SubjectUserName)

Stage 28: `extend`

| extend SubjectDomainName = tostring(EventData.SubjectDomainName)

Stage 29: `summarize`

| summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName

Stage 30: `source`

SecurityEvent

Stage 31: `where`

| where EventID == '4663'

Stage 32: `where`

| where ObjectType == 'Key'

Stage 33: `where`

| where ObjectName == aadHealthMonAgentRegKey

Stage 34: `extend`

| extend Process = tostring(split(ProcessName, '\\', -1)[-1])

Stage 35: `where`

| where Process !in (aadConnectHealthProcs)

Stage 36: `summarize`

| summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName

Stage 37: `source`

WindowsEvent

Stage 38: `where`

| where EventID == '4663' and EventData has aadHealthMonAgentRegKey

Stage 39: `extend`

| extend ObjectType = tostring(EventData.ObjectType)

Stage 40: `where`

| where ObjectType == 'Key'

Stage 41: `extend`

| extend ObjectName = tostring(EventData.ObjectName)

Stage 42: `where`

| where ObjectName == aadHealthMonAgentRegKey

Stage 43: `extend`

| extend ProcessName = tostring(EventData.ProcessName)

Stage 44: `extend`

| extend Process = tostring(split(ProcessName, '\\')[-1])

Stage 45: `where`

| where Process !in (aadConnectHealthProcs)

Stage 46: `extend`

| extend Account =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))

Stage 47: `extend`

| extend SubjectUserName = tostring(EventData.SubjectUserName)

Stage 48: `extend`

| extend SubjectDomainName = tostring(EventData.SubjectDomainName)

Stage 49: `summarize`

| summarize StartTime = max(TimeGenerated), EndTime = min(TimeGenerated), count() by EventID, Account, Computer, Process, SubjectUserName, SubjectDomainName, ObjectName, ObjectType, ProcessName

Stage 50: `extend`

| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))

Stage 51: `extend`

| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)

Stage 52: `extend`

| extend Name = tostring(split(Account, "\\")[1]), NTDomain = tostring(split(Account, "\\")[0])

Stage 53: `project-away`

| project-away DomainIndex

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Stage	Field	Kind	Excluded values
15	`Process`	in	`Microsoft.Azure.ActiveDirectory.Synchronization.Upgrader.exe`, `Microsoft.Identity.AadConnect.Health.AadSync.Host.exe`, `Microsoft.Identity.Health.AadSync.MonitoringAgent.Startup.exe`, `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`, `miiserver.exe`
25	`Process`	in	`Microsoft.Azure.ActiveDirectory.Synchronization.Upgrader.exe`, `Microsoft.Identity.AadConnect.Health.AadSync.Host.exe`, `Microsoft.Identity.Health.AadSync.MonitoringAgent.Startup.exe`, `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`, `miiserver.exe`
35	`Process`	in	`Microsoft.Azure.ActiveDirectory.Synchronization.Upgrader.exe`, `Microsoft.Identity.AadConnect.Health.AadSync.Host.exe`, `Microsoft.Identity.Health.AadSync.MonitoringAgent.Startup.exe`, `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`, `miiserver.exe`
45	`Process`	in	`Microsoft.Azure.ActiveDirectory.Synchronization.Upgrader.exe`, `Microsoft.Identity.AadConnect.Health.AadSync.Host.exe`, `Microsoft.Identity.Health.AadSync.MonitoringAgent.Startup.exe`, `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`, `miiserver.exe`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`EventData`	match	`\\REGISTRY\\MACHINE\\SOFTWARE\\Microsoft\\Microsoft Online\\Reporting\\MonitoringAgent`
`EventID`	eq	`4656` transforms: `cased` corpus 19 (splunk 15, kusto 4) `4663` transforms: `cased` corpus 34 (splunk 29, kusto 5)
`ObjectName`	eq	`\\REGISTRY\\MACHINE\\SOFTWARE\\Microsoft\\Microsoft Online\\Reporting\\MonitoringAgent` transforms: `cased`
`ObjectType`	eq	`Key` transforms: `cased` corpus 8 (sigma 4, kusto 4)

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field	Source
`Account`	`summarize`
`Computer`	`summarize`
`EndTime`	`summarize`
`EventID`	`summarize`
`ObjectName`	`summarize`
`ObjectType`	`summarize`
`Process`	`summarize`
`ProcessName`	`summarize`
`StartTime`	`summarize`
`SubjectDomainName`	`summarize`
`SubjectUserName`	`summarize`
`HostName`	`extend`
`HostNameDomain`	`extend`
`NTDomain`	`extend`
`Name`	`extend`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Microsoft Entra ID Health Monitoring Agent Registry Keys Access

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Stage 0: let

Stage 1: union

Stage 2: source time_window=86400s

Stage 3: where

Stage 4: where

Stage 5: extend

Stage 6: mv-expand

Stage 7: evaluate

Stage 8: extend

Stage 9: evaluate

Stage 10: extend

Stage 11: where

Stage 12: where

Stage 13: extend

Stage 14: extend

Stage 15: where

Stage 16: summarize

Stage 17: source

Stage 18: where

Stage 19: extend

Stage 20: where

Stage 21: extend

Stage 22: where

Stage 23: extend

Stage 24: extend

Stage 25: where

Stage 26: extend

Stage 27: extend

Stage 28: extend

Stage 29: summarize

Stage 30: source

Stage 31: where

Stage 32: where

Stage 33: where

Stage 34: extend

Stage 35: where

Stage 36: summarize

Stage 37: source

Stage 38: where

Stage 39: extend

Stage 40: where

Stage 41: extend

Stage 42: where

Stage 43: extend

Stage 44: extend

Stage 45: where

Stage 46: extend

Stage 47: extend

Stage 48: extend

Stage 49: summarize

Stage 50: extend

Stage 51: extend

Stage 52: extend

Stage 53: project-away