User account created without expected attributes defined

let threshold = 10;
let default_ad_attributes = dynamic(["LastDirSyncTime", "StsRefreshTokensValidFrom", "Included Updated Properties", "AccountEnabled", "Action Client Name", "SourceAnchor"]);
let addUsers = AuditLogs
| where OperationName =~ "Add user"
| where Result =~ "success"
| extend AccountProperties = TargetResources[0].modifiedProperties
| mv-expand AccountProperties
;
addUsers
| evaluate bag_unpack(AccountProperties) : (displayName:string, oldValue: string, newValue: string , TenantId : string, SourceSystem : string, TimeGenerated : datetime, ResourceId : string, OperationName : string, OperationVersion : string, Category : string, ResultType : string, ResultSignature : string, ResultDescription : string, DurationMs : long, CorrelationId : string, Resource : string, ResourceGroup : string, ResourceProvider : string, Identity : string, Level : string, Location : string, AdditionalDetails : dynamic, Id : string, InitiatedBy : dynamic, LoggedByService : string, Result : string, ResultReason : string, TargetResources : dynamic, AADTenantId : string, ActivityDisplayName : string, ActivityDateTime : datetime, AADOperationType : string, Type : string)
| extend displayName = column_ifexists("displayName", "Unknown Value")
| summarize count() by displayName, TenantId
| where displayName !in (default_ad_attributes)
| top threshold by count_ desc
| summarize make_set(displayName) by TenantId
| join kind=inner (
addUsers
| extend CreatingUserPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)
| extend CreatingAadUserId = tostring(InitiatedBy.user.id)
| extend CreatingUserIPAddress = tostring(InitiatedBy.user.ipAddress)
| extend CreatedUserPrincipalName = tostring(TargetResources[0].userPrincipalName)
| extend PropName = tostring(AccountProperties.displayName)) 
on TenantId
| summarize makeset(PropName) by TimeGenerated, CorrelationId, CreatedUserPrincipalName, CreatingUserPrincipalName, CreatingAadUserId, CreatingUserIPAddress, tostring(set_displayName)
| extend missing_props = set_difference(todynamic(set_displayName), set_PropName)
| where array_length(missing_props) > 0
| join kind=innerunique (
AuditLogs
| where Result =~ "success"
| where OperationName =~ "Add user"
| extend CreatedUserPrincipalName = tostring(TargetResources[0].userPrincipalName)) 
on CorrelationId, CreatedUserPrincipalName
| extend ExpectedProperties = set_displayName
| project-away set_displayName, set_PropName
| extend InitiatingAccountName = tostring(split(CreatingUserPrincipalName, "@")[0]), InitiatingAccountUPNSuffix = tostring(split(CreatingUserPrincipalName, "@")[1])
| extend TargetAccountName = tostring(split(CreatedUserPrincipalName, "@")[0]), TargetAccountUPNSuffix = tostring(split(CreatedUserPrincipalName, "@")[1])

entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: CreatingUserPrincipalName
    identifier: FullName
  - columnName: InitiatingAccountName
    identifier: Name
  - columnName: InitiatingAccountUPNSuffix
    identifier: UPNSuffix
- entityType: Account
  fieldMappings:
  - columnName: CreatingAadUserId
    identifier: AadUserId
- entityType: Account
  fieldMappings:
  - columnName: CreatedUserPrincipalName
    identifier: FullName
  - columnName: TargetAccountName
    identifier: Name
  - columnName: TargetAccountUPNSuffix
    identifier: UPNSuffix
- entityType: IP
  fieldMappings:
  - columnName: CreatingUserIPAddress
    identifier: Address
query: |
  let threshold = 10;
  let default_ad_attributes = dynamic(["LastDirSyncTime", "StsRefreshTokensValidFrom", "Included Updated Properties", "AccountEnabled", "Action Client Name", "SourceAnchor"]);
  let addUsers = AuditLogs
  | where OperationName =~ "Add user"
  | where Result =~ "success"
  | extend AccountProperties = TargetResources[0].modifiedProperties
  | mv-expand AccountProperties
  ;
  addUsers
  | evaluate bag_unpack(AccountProperties) : (displayName:string, oldValue: string, newValue: string , TenantId : string, SourceSystem : string, TimeGenerated : datetime, ResourceId : string, OperationName : string, OperationVersion : string, Category : string, ResultType : string, ResultSignature : string, ResultDescription : string, DurationMs : long, CorrelationId : string, Resource : string, ResourceGroup : string, ResourceProvider : string, Identity : string, Level : string, Location : string, AdditionalDetails : dynamic, Id : string, InitiatedBy : dynamic, LoggedByService : string, Result : string, ResultReason : string, TargetResources : dynamic, AADTenantId : string, ActivityDisplayName : string, ActivityDateTime : datetime, AADOperationType : string, Type : string)
  | extend displayName = column_ifexists("displayName", "Unknown Value")
  | summarize count() by displayName, TenantId
  | where displayName !in (default_ad_attributes)
  | top threshold by count_ desc
  | summarize make_set(displayName) by TenantId
  | join kind=inner (
  addUsers
  | extend CreatingUserPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)
  | extend CreatingAadUserId = tostring(InitiatedBy.user.id)
  | extend CreatingUserIPAddress = tostring(InitiatedBy.user.ipAddress)
  | extend CreatedUserPrincipalName = tostring(TargetResources[0].userPrincipalName)
  | extend PropName = tostring(AccountProperties.displayName)) 
  on TenantId
  | summarize makeset(PropName) by TimeGenerated, CorrelationId, CreatedUserPrincipalName, CreatingUserPrincipalName, CreatingAadUserId, CreatingUserIPAddress, tostring(set_displayName)
  | extend missing_props = set_difference(todynamic(set_displayName), set_PropName)
  | where array_length(missing_props) > 0
  | join kind=innerunique (
  AuditLogs
  | where Result =~ "success"
  | where OperationName =~ "Add user"
  | extend CreatedUserPrincipalName = tostring(TargetResources[0].userPrincipalName)) 
  on CorrelationId, CreatedUserPrincipalName
  | extend ExpectedProperties = set_displayName
  | project-away set_displayName, set_PropName
  | extend InitiatingAccountName = tostring(split(CreatingUserPrincipalName, "@")[0]), InitiatingAccountUPNSuffix = tostring(split(CreatingUserPrincipalName, "@")[1])
  | extend TargetAccountName = tostring(split(CreatedUserPrincipalName, "@")[0]), TargetAccountUPNSuffix = tostring(split(CreatedUserPrincipalName, "@")[1])
metadata:
  categories:
    domains:
    - Security - Others
  source:
    kind: Community
  author:
    name: Microsoft Security Research
  support:
    tier: Community
tags:
- AADSecOpsGuide
queryFrequency: 1d
id: dc99e38c-f4e9-4837-94d7-353ac0b01a77
version: 1.1.0
severity: Low
relevantTechniques:
- T1136.003
name: User account created without expected attributes defined
kind: Scheduled
tactics:
- Persistence
requiredDataConnectors:
- dataTypes:
  - AuditLogs
  connectorId: AzureActiveDirectory
description: |
  'This query looks for accounts being created that do not have attributes populated that are commonly populated in the tenant.
    Attackers may attempt to add accounts as a means of establishing persistant access to an environment, looking for anomalies in created accounts may help identify illegitimately created accounts.
    Created accounts should be investigated to ensure they were legitimated created.
    Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-user-accounts#accounts-not-following-naming-policies'
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/Useraccountcreatedwithoutexpectedattributesdefined.yaml
triggerOperator: gt
triggerThreshold: 0
queryPeriod: 1d

{
  "$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/dc99e38c-f4e9-4837-94d7-353ac0b01a77')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/dc99e38c-f4e9-4837-94d7-353ac0b01a77')]",
      "properties": {
        "alertRuleTemplateName": "dc99e38c-f4e9-4837-94d7-353ac0b01a77",
        "customDetails": null,
        "description": "'This query looks for accounts being created that do not have attributes populated that are commonly populated in the tenant.\n  Attackers may attempt to add accounts as a means of establishing persistant access to an environment, looking for anomalies in created accounts may help identify illegitimately created accounts.\n  Created accounts should be investigated to ensure they were legitimated created.\n  Ref: https://docs.microsoft.com/azure/active-directory/fundamentals/security-operations-user-accounts#accounts-not-following-naming-policies'\n",
        "displayName": "User account created without expected attributes defined",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "CreatingUserPrincipalName",
                "identifier": "FullName"
              },
              {
                "columnName": "InitiatingAccountName",
                "identifier": "Name"
              },
              {
                "columnName": "InitiatingAccountUPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "CreatingAadUserId",
                "identifier": "AadUserId"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "CreatedUserPrincipalName",
                "identifier": "FullName"
              },
              {
                "columnName": "TargetAccountName",
                "identifier": "Name"
              },
              {
                "columnName": "TargetAccountUPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "CreatingUserIPAddress",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/Useraccountcreatedwithoutexpectedattributesdefined.yaml",
        "query": "let threshold = 10;\nlet default_ad_attributes = dynamic([\"LastDirSyncTime\", \"StsRefreshTokensValidFrom\", \"Included Updated Properties\", \"AccountEnabled\", \"Action Client Name\", \"SourceAnchor\"]);\nlet addUsers = AuditLogs\n| where OperationName =~ \"Add user\"\n| where Result =~ \"success\"\n| extend AccountProperties = TargetResources[0].modifiedProperties\n| mv-expand AccountProperties\n;\naddUsers\n| evaluate bag_unpack(AccountProperties) : (displayName:string, oldValue: string, newValue: string , TenantId : string, SourceSystem : string, TimeGenerated : datetime, ResourceId : string, OperationName : string, OperationVersion : string, Category : string, ResultType : string, ResultSignature : string, ResultDescription : string, DurationMs : long, CorrelationId : string, Resource : string, ResourceGroup : string, ResourceProvider : string, Identity : string, Level : string, Location : string, AdditionalDetails : dynamic, Id : string, InitiatedBy : dynamic, LoggedByService : string, Result : string, ResultReason : string, TargetResources : dynamic, AADTenantId : string, ActivityDisplayName : string, ActivityDateTime : datetime, AADOperationType : string, Type : string)\n| extend displayName = column_ifexists(\"displayName\", \"Unknown Value\")\n| summarize count() by displayName, TenantId\n| where displayName !in (default_ad_attributes)\n| top threshold by count_ desc\n| summarize make_set(displayName) by TenantId\n| join kind=inner (\naddUsers\n| extend CreatingUserPrincipalName = tostring(parse_json(tostring(InitiatedBy.user)).userPrincipalName)\n| extend CreatingAadUserId = tostring(InitiatedBy.user.id)\n| extend CreatingUserIPAddress = tostring(InitiatedBy.user.ipAddress)\n| extend CreatedUserPrincipalName = tostring(TargetResources[0].userPrincipalName)\n| extend PropName = tostring(AccountProperties.displayName)) \non TenantId\n| summarize makeset(PropName) by TimeGenerated, CorrelationId, CreatedUserPrincipalName, CreatingUserPrincipalName, CreatingAadUserId, CreatingUserIPAddress, tostring(set_displayName)\n| extend missing_props = set_difference(todynamic(set_displayName), set_PropName)\n| where array_length(missing_props) > 0\n| join kind=innerunique (\nAuditLogs\n| where Result =~ \"success\"\n| where OperationName =~ \"Add user\"\n| extend CreatedUserPrincipalName = tostring(TargetResources[0].userPrincipalName)) \non CorrelationId, CreatedUserPrincipalName\n| extend ExpectedProperties = set_displayName\n| project-away set_displayName, set_PropName\n| extend InitiatingAccountName = tostring(split(CreatingUserPrincipalName, \"@\")[0]), InitiatingAccountUPNSuffix = tostring(split(CreatingUserPrincipalName, \"@\")[1])\n| extend TargetAccountName = tostring(split(CreatedUserPrincipalName, \"@\")[0]), TargetAccountUPNSuffix = tostring(split(CreatedUserPrincipalName, \"@\")[1])\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "Low",
        "subTechniques": [
          "T1136.003"
        ],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Persistence"
        ],
        "tags": [
          "AADSecOpsGuide"
        ],
        "techniques": [
          "T1136"
        ],
        "templateVersion": "1.1.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}