User account created without expected attributes defined

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Id	dc99e38c-f4e9-4837-94d7-353ac0b01a77
Rulename	User account created without expected attributes defined
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
Severity	Low
Tactics	Persistence
Techniques	T1136.003
Required data connectors	AzureActiveDirectory
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/AuditLogs/Useraccountcreatedwithoutexpectedattributesdefined.yaml
Version	1.1.0
Arm template	dc99e38c-f4e9-4837-94d7-353ac0b01a77.json

KQL

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])

YAML

queryFrequency: 1d
requiredDataConnectors:
- connectorId: AzureActiveDirectory
  dataTypes:
  - AuditLogs
tags:
- AADSecOpsGuide
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/AuditLogs/Useraccountcreatedwithoutexpectedattributesdefined.yaml
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])  
entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: CreatingUserPrincipalName
  - identifier: Name
    columnName: InitiatingAccountName
  - identifier: UPNSuffix
    columnName: InitiatingAccountUPNSuffix
- entityType: Account
  fieldMappings:
  - identifier: AadUserId
    columnName: CreatingAadUserId
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: CreatedUserPrincipalName
  - identifier: Name
    columnName: TargetAccountName
  - identifier: UPNSuffix
    columnName: TargetAccountUPNSuffix
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: CreatingUserIPAddress
relevantTechniques:
- T1136.003
name: User account created without expected attributes defined
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'  
metadata:
  support:
    tier: Community
  categories:
    domains:
    - Security - Others
  source:
    kind: Community
  author:
    name: Microsoft Security Research
severity: Low
queryPeriod: 1d
triggerOperator: gt
kind: Scheduled
tactics:
- Persistence
id: dc99e38c-f4e9-4837-94d7-353ac0b01a77
version: 1.1.0
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": [
    {
      "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"
    }
  ]
}