Service Principal Name SPN Assigned to User Account

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Id	875d0eb1-883a-4191-bd0e-dbfdeb95a464
Rulename	Service Principal Name (SPN) Assigned to User Account
Description	This query identifies whether an Active Directory user object was assigned a service principal name which could indicate that an adversary is preparing for performing Kerberoasting. This query checks for event id 5136, that the Object Class field is “user” and the LDAP Display Name is “servicePrincipalName”. Ref: https://thevivi.net/assets/docs/2019/theVIVI-AD-Security-Workshop_AfricaHackon2019.pdf
Severity	Medium
Tactics	PrivilegeEscalation
Techniques	T1134
Required data connectors	SecurityEvents
Kind	Scheduled
Query frequency	1h
Query period	1h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/UserPrincipalNameAssignedToUserAccount.yaml
Version	1.0.4
Arm template	875d0eb1-883a-4191-bd0e-dbfdeb95a464.json

KQL

SecurityEvent
| where EventID == 5136 
| parse EventData with * 'AttributeLDAPDisplayName">' AttributeLDAPDisplayName "<" *
| parse EventData with * 'ObjectClass">' ObjectClass "<" *
| where AttributeLDAPDisplayName == "servicePrincipalName" and  ObjectClass == "user"
| parse EventData with * 'ObjectDN">' ObjectDN "<" *
| parse EventData with * 'AttributeValue">' AttributeValue "<" *
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by Computer, SubjectAccount, ObjectDN, AttributeValue, SubjectUserName, SubjectDomainName, SubjectUserSid
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| project-away DomainIndex

YAML

severity: Medium
relevantTechniques:
- T1134
queryFrequency: 1h
kind: Scheduled
version: 1.0.4
metadata:
  support:
    tier: Community
  categories:
    domains:
    - Security - Others
    - Identity
  author:
    name: Vasileios Paschalidis
  source:
    kind: Community
triggerOperator: gt
description: |
  'This query identifies whether an Active Directory user object was assigned a service principal name which could indicate that an adversary is preparing for performing Kerberoasting. 
  This query checks for event id 5136, that the Object Class field is "user" and the LDAP Display Name is "servicePrincipalName".
  Ref: https://thevivi.net/assets/docs/2019/theVIVI-AD-Security-Workshop_AfricaHackon2019.pdf'  
queryPeriod: 1h
id: 875d0eb1-883a-4191-bd0e-dbfdeb95a464
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: SubjectAccount
    identifier: FullName
  - columnName: SubjectUserName
    identifier: Name
  - columnName: SubjectDomainName
    identifier: NTDomain
- entityType: Account
  fieldMappings:
  - columnName: SubjectUserSid
    identifier: Sid
- entityType: Host
  fieldMappings:
  - columnName: Computer
    identifier: FullName
  - columnName: HostName
    identifier: HostName
  - columnName: HostNameDomain
    identifier: NTDomain
tactics:
- PrivilegeEscalation
name: Service Principal Name (SPN) Assigned to User Account
triggerThreshold: 0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/UserPrincipalNameAssignedToUserAccount.yaml
query: |
  SecurityEvent
  | where EventID == 5136 
  | parse EventData with * 'AttributeLDAPDisplayName">' AttributeLDAPDisplayName "<" *
  | parse EventData with * 'ObjectClass">' ObjectClass "<" *
  | where AttributeLDAPDisplayName == "servicePrincipalName" and  ObjectClass == "user"
  | parse EventData with * 'ObjectDN">' ObjectDN "<" *
  | parse EventData with * 'AttributeValue">' AttributeValue "<" *
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by Computer, SubjectAccount, ObjectDN, AttributeValue, SubjectUserName, SubjectDomainName, SubjectUserSid
  | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
  | project-away DomainIndex  
requiredDataConnectors:
- dataTypes:
  - SecurityEvent
  connectorId: SecurityEvents

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2023-02-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/875d0eb1-883a-4191-bd0e-dbfdeb95a464')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/875d0eb1-883a-4191-bd0e-dbfdeb95a464')]",
      "properties": {
        "alertRuleTemplateName": "875d0eb1-883a-4191-bd0e-dbfdeb95a464",
        "customDetails": null,
        "description": "'This query identifies whether an Active Directory user object was assigned a service principal name which could indicate that an adversary is preparing for performing Kerberoasting. \nThis query checks for event id 5136, that the Object Class field is \"user\" and the LDAP Display Name is \"servicePrincipalName\".\nRef: https://thevivi.net/assets/docs/2019/theVIVI-AD-Security-Workshop_AfricaHackon2019.pdf'\n",
        "displayName": "Service Principal Name (SPN) Assigned to User Account",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "SubjectAccount",
                "identifier": "FullName"
              },
              {
                "columnName": "SubjectUserName",
                "identifier": "Name"
              },
              {
                "columnName": "SubjectDomainName",
                "identifier": "NTDomain"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "SubjectUserSid",
                "identifier": "Sid"
              }
            ]
          },
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "Computer",
                "identifier": "FullName"
              },
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "HostNameDomain",
                "identifier": "NTDomain"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/UserPrincipalNameAssignedToUserAccount.yaml",
        "query": "SecurityEvent\n| where EventID == 5136 \n| parse EventData with * 'AttributeLDAPDisplayName\">' AttributeLDAPDisplayName \"<\" *\n| parse EventData with * 'ObjectClass\">' ObjectClass \"<\" *\n| where AttributeLDAPDisplayName == \"servicePrincipalName\" and  ObjectClass == \"user\"\n| parse EventData with * 'ObjectDN\">' ObjectDN \"<\" *\n| parse EventData with * 'AttributeValue\">' AttributeValue \"<\" *\n| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by Computer, SubjectAccount, ObjectDN, AttributeValue, SubjectUserName, SubjectDomainName, SubjectUserSid\n| extend HostName = tostring(split(Computer, \".\")[0]), DomainIndex = toint(indexof(Computer, '.'))\n| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)\n| project-away DomainIndex\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "PrivilegeEscalation"
        ],
        "techniques": [
          "T1134"
        ],
        "templateVersion": "1.0.4",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}