Suspicious Entra ID Joined Device Update

id: 3a3c6835-0086-40ca-b033-a93bf26d878f
name: Suspicious Entra ID Joined Device Update
description: |
  'This query looks for suspicious updates to an Microsoft Entra ID joined device where the device name is changed and the device falls out of compliance.
  This could occur when a threat actor updates the details of an Autopilot provisioned device using a stolen device ticket, in order to access certificates and keys.
  Ref: https://dirkjanm.io/assets/raw/Insomnihack%20Breaking%20and%20fixing%20Azure%20AD%20device%20identity%20security.pdf'
severity: Medium
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
      - AuditLogs
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
status: Available
tactics:
  - CredentialAccess
relevantTechniques:
  - T1528
query: |
  AuditLogs
  | where OperationName =~ "Update device"
  | mv-apply TargetResource=TargetResources on (
      where TargetResource.type =~ "Device"
      | extend ModifiedProperties = TargetResource.modifiedProperties
      | extend DeviceId = TargetResource.id)
  | mv-apply Prop=ModifiedProperties on ( 
      where Prop.displayName =~ "CloudDisplayName"
      | extend OldName = Prop.oldValue 
      | extend NewName = Prop.newValue)
  | mv-apply Prop=ModifiedProperties on ( 
      where Prop.displayName =~ "IsCompliant"
      | extend OldComplianceState = Prop.oldValue  
      | extend NewComplianceState = Prop.newValue)
  | mv-apply Prop=ModifiedProperties on ( 
      where Prop.displayName =~ "TargetId.DeviceTrustType"
      | extend OldTrustType = Prop.oldValue  
      | extend NewTrustType = Prop.newValue)
  | mv-apply Prop=ModifiedProperties on ( 
      where Prop.displayName =~ "Included Updated Properties" 
      | extend UpdatedProperties = Prop.newValue)
  | extend OldDeviceName = tostring(parse_json(tostring(OldName))[0])
  | extend NewDeviceName = tostring(parse_json(tostring(NewName))[0])
  | extend OldComplianceState = tostring(parse_json(tostring(OldComplianceState))[0])
  | extend NewComplianceState = tostring(parse_json(tostring(NewComplianceState))[0])
  | extend InitiatingAppName = tostring(InitiatedBy.app.displayName)
  | extend InitiatingAppServicePrincipalId = tostring(InitiatedBy.app.servicePrincipalId)
  | extend InitiatingUserPrincipalName = tostring(InitiatedBy.user.userPrincipalName)
  | extend InitiatingAadUserId = tostring(InitiatedBy.user.id)
  | extend InitiatingIpAddress = tostring(iff(isnotempty(InitiatedBy.user.ipAddress), InitiatedBy.user.ipAddress, InitiatedBy.app.ipAddress))
  | extend UpdatedPropertiesCount = array_length(split(UpdatedProperties, ','))
  | where OldDeviceName != NewDeviceName
  | where OldComplianceState =~ 'true' and NewComplianceState =~ 'false'
  // Most common is transferring from AAD Registered to AAD Joined - we just want AAD Joined devices
  | where NewTrustType == '"AzureAd"' and OldTrustType != '"Workplace"'
  // We can modify this value to tune FPs - more properties changed about the device beyond its name the more suspicious it could be
  | where UpdatedPropertiesCount > 1
  | project-reorder TimeGenerated, DeviceId, NewDeviceName, OldDeviceName, NewComplianceState, InitiatingUserPrincipalName, InitiatingAadUserId, InitiatingAppName, InitiatingAppServicePrincipalId, InitiatingIpAddress, AADOperationType, OldTrustType, NewTrustType, UpdatedProperties, UpdatedPropertiesCount
  | extend InitiatedByName = tostring(split(InitiatingUserPrincipalName,'@',0)[0]), InitiatedByUPNSuffix = tostring(split(InitiatingUserPrincipalName,'@',1)[0])
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: NewDeviceName
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: OldDeviceName
  - entityType: Host
    fieldMappings:
      - identifier: AzureID
        columnName: DeviceId
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: InitiatingUserPrincipalName    
      - identifier: Name
        columnName: InitiatedByName      
      - identifier: UPNSuffix
        columnName: InitiatedByUPNSuffix
  - entityType: Account
    fieldMappings:
      - identifier: AadUserId
        columnName: InitiatingAadUserId
  - entityType: Account
    fieldMappings:
      - identifier: AadUserId
        columnName: InitiatingAppServicePrincipalId
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: InitiatingIpAddress
alertDetailsOverride:
  alertDisplayNameFormat: Suspicious Entra ID Joined Device Update {{OldDeviceName}} renamed to {{NewDeviceName}} and {{UpdatedPropertiesCount}} properties changed
  alertDescriptionFormat: |
    This query looks for suspicious updates to an Microsoft Entra ID joined device where the device name is changed and the device falls out of compliance.
    In this case {{OldDeviceName}} was renamed to {{NewDeviceName}} and {{UpdatedPropertiesCount}} properties were changed.
    This could occur when a threat actor updates the details of an Autopilot provisioned device using a stolen device ticket, in order to access certificates and keys.
    Ref: https://dirkjanm.io/assets/raw/Insomnihack%20Breaking%20and%20fixing%20Azure%20AD%20device%20identity%20security.pdf
version: 1.0.4
kind: Scheduled