New user created and added to the built-in administrators group

(union isfuzzy=true
(SecurityEvent
| where EventID == 4720
| where AccountType == "User"
| project CreatedUserTime = TimeGenerated, CreatedUserEventID = EventID, CreatedUserActivity = Activity, Computer = toupper(Computer), 
CreatedUser = tolower(TargetAccount), CreatedUserSid = TargetSid, AccountUsedToCreateUser = strcat(SubjectAccount), SidofAccountUsedToCreateUser = SubjectUserSid
),
(WindowsEvent
| where EventID == 4720
| extend SubjectUserSid = tostring(EventData.SubjectUserSid)
| extend AccountType=case(EventData.SubjectUserName endswith "$" or SubjectUserSid in ("S-1-5-18", "S-1-5-19", "S-1-5-20"), "Machine", isempty(SubjectUserSid), "", "User")
| where AccountType == "User"
| extend SubjectAccount = strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
| extend TargetAccount = strcat(EventData.TargetDomainName,"\\", EventData.TargetUserName)
| extend Activity="4720 - A user account was created."
| extend TargetSid = tostring(EventData.TargetSid)
| project CreatedUserTime = TimeGenerated, CreatedUserEventID = EventID, CreatedUserActivity = Activity, Computer = toupper(Computer), 
CreatedUser = tolower(TargetAccount), CreatedUserSid = TargetSid, AccountUsedToCreateUser = strcat(SubjectAccount), SidofAccountUsedToCreateUser = SubjectUserSid
))
| join ((union isfuzzy=true
(SecurityEvent 
| where AccountType == "User"
// 4732 - A member was added to a security-enabled local group
| where EventID == 4732
// TargetSid is the builin Admins group: S-1-5-32-544
| where TargetSid == "S-1-5-32-544"
| project GroupAddTime = TimeGenerated, GroupAddEventID = EventID, GroupAddActivity = Activity, Computer = toupper(Computer), GroupName = tolower(TargetAccount), 
GroupSid = TargetSid, AccountThatAddedUser = SubjectAccount, SIDofAccountThatAddedUser = SubjectUserSid, CreatedUserSid = MemberSid
),
(  WindowsEvent 
// 4732 - A member was added to a security-enabled local group
| where EventID == 4732 and EventData has "S-1-5-32-544"
//TargetSid is the builin Admins group: S-1-5-32-544
| extend SubjectUserSid = tostring(EventData.SubjectUserSid)
| extend AccountType=case(EventData.SubjectUserName endswith "$" or SubjectUserSid in ("S-1-5-18", "S-1-5-19", "S-1-5-20"), "Machine", isempty(SubjectUserSid), "", "User")
| where AccountType == "User"
| extend TargetSid = tostring(EventData.TargetSid)
| where TargetSid == "S-1-5-32-544"
| extend SubjectAccount = strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
| extend TargetAccount = strcat(EventData.TargetDomainName,"\\", EventData.TargetUserName)
| extend Activity="4732 - A member was added to a security-enabled local group."
| extend MemberSid = tostring(EventData.MemberSid)
| project GroupAddTime = TimeGenerated, GroupAddEventID = EventID, GroupAddActivity = Activity, Computer = toupper(Computer), GroupName = tolower(TargetAccount), 
GroupSid = TargetSid, AccountThatAddedUser = SubjectAccount, SIDofAccountThatAddedUser = SubjectUserSid, CreatedUserSid = MemberSid)
))
on CreatedUserSid
//Create User first, then the add to the group.
| project Computer, CreatedUserTime, CreatedUserEventID, CreatedUserActivity, CreatedUser, CreatedUserSid, GroupAddTime, GroupAddEventID, 
GroupAddActivity, AccountUsedToCreateUser, GroupName, GroupSid, AccountThatAddedUser, SIDofAccountThatAddedUser 
| extend timestamp = CreatedUserTime, AccountCustomEntity = CreatedUser, HostCustomEntity = Computer

severity: Low
triggerThreshold: 0
metadata:
  source:
    kind: Community
  support:
    tier: Community
  categories:
    domains:
    - Security - Others
    - Identity
  author:
    name: Shain
queryFrequency: 1d
requiredDataConnectors:
- connectorId: SecurityEvents
  dataTypes:
  - SecurityEvent
- connectorId: WindowsSecurityEvents
  dataTypes:
  - SecurityEvents
- connectorId: WindowsForwardedEvents
  dataTypes:
  - WindowsEvent
id: aa1eff90-29d4-49dc-a3ea-b65199f516db
version: 1.1.3
name: New user created and added to the built-in administrators group
kind: Scheduled
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/UserCreatedAddedToBuiltinAdmins_1d.yaml
queryPeriod: 1d
relevantTechniques:
- T1098
- T1078
triggerOperator: gt
tactics:
- Persistence
- PrivilegeEscalation
query: |
  (union isfuzzy=true
  (SecurityEvent
  | where EventID == 4720
  | where AccountType == "User"
  | project CreatedUserTime = TimeGenerated, CreatedUserEventID = EventID, CreatedUserActivity = Activity, Computer = toupper(Computer), 
  CreatedUser = tolower(TargetAccount), CreatedUserSid = TargetSid, AccountUsedToCreateUser = strcat(SubjectAccount), SidofAccountUsedToCreateUser = SubjectUserSid
  ),
  (WindowsEvent
  | where EventID == 4720
  | extend SubjectUserSid = tostring(EventData.SubjectUserSid)
  | extend AccountType=case(EventData.SubjectUserName endswith "$" or SubjectUserSid in ("S-1-5-18", "S-1-5-19", "S-1-5-20"), "Machine", isempty(SubjectUserSid), "", "User")
  | where AccountType == "User"
  | extend SubjectAccount = strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
  | extend TargetAccount = strcat(EventData.TargetDomainName,"\\", EventData.TargetUserName)
  | extend Activity="4720 - A user account was created."
  | extend TargetSid = tostring(EventData.TargetSid)
  | project CreatedUserTime = TimeGenerated, CreatedUserEventID = EventID, CreatedUserActivity = Activity, Computer = toupper(Computer), 
  CreatedUser = tolower(TargetAccount), CreatedUserSid = TargetSid, AccountUsedToCreateUser = strcat(SubjectAccount), SidofAccountUsedToCreateUser = SubjectUserSid
  ))
  | join ((union isfuzzy=true
  (SecurityEvent 
  | where AccountType == "User"
  // 4732 - A member was added to a security-enabled local group
  | where EventID == 4732
  // TargetSid is the builin Admins group: S-1-5-32-544
  | where TargetSid == "S-1-5-32-544"
  | project GroupAddTime = TimeGenerated, GroupAddEventID = EventID, GroupAddActivity = Activity, Computer = toupper(Computer), GroupName = tolower(TargetAccount), 
  GroupSid = TargetSid, AccountThatAddedUser = SubjectAccount, SIDofAccountThatAddedUser = SubjectUserSid, CreatedUserSid = MemberSid
  ),
  (  WindowsEvent 
  // 4732 - A member was added to a security-enabled local group
  | where EventID == 4732 and EventData has "S-1-5-32-544"
  //TargetSid is the builin Admins group: S-1-5-32-544
  | extend SubjectUserSid = tostring(EventData.SubjectUserSid)
  | extend AccountType=case(EventData.SubjectUserName endswith "$" or SubjectUserSid in ("S-1-5-18", "S-1-5-19", "S-1-5-20"), "Machine", isempty(SubjectUserSid), "", "User")
  | where AccountType == "User"
  | extend TargetSid = tostring(EventData.TargetSid)
  | where TargetSid == "S-1-5-32-544"
  | extend SubjectAccount = strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
  | extend TargetAccount = strcat(EventData.TargetDomainName,"\\", EventData.TargetUserName)
  | extend Activity="4732 - A member was added to a security-enabled local group."
  | extend MemberSid = tostring(EventData.MemberSid)
  | project GroupAddTime = TimeGenerated, GroupAddEventID = EventID, GroupAddActivity = Activity, Computer = toupper(Computer), GroupName = tolower(TargetAccount), 
  GroupSid = TargetSid, AccountThatAddedUser = SubjectAccount, SIDofAccountThatAddedUser = SubjectUserSid, CreatedUserSid = MemberSid)
  ))
  on CreatedUserSid
  //Create User first, then the add to the group.
  | project Computer, CreatedUserTime, CreatedUserEventID, CreatedUserActivity, CreatedUser, CreatedUserSid, GroupAddTime, GroupAddEventID, 
  GroupAddActivity, AccountUsedToCreateUser, GroupName, GroupSid, AccountThatAddedUser, SIDofAccountThatAddedUser 
  | extend timestamp = CreatedUserTime, AccountCustomEntity = CreatedUser, HostCustomEntity = Computer  
entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: AccountCustomEntity
  - identifier: Sid
    columnName: CreatedUserSid
- entityType: Host
  fieldMappings:
  - identifier: FullName
    columnName: HostCustomEntity
description: |
  'Identifies when a user account was created and then added to the builtin Administrators group in the same day.
  This should be monitored closely and all additions reviewed.'  

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/aa1eff90-29d4-49dc-a3ea-b65199f516db')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/aa1eff90-29d4-49dc-a3ea-b65199f516db')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "New user created and added to the built-in administrators group",
        "description": "'Identifies when a user account was created and then added to the builtin Administrators group in the same day.\nThis should be monitored closely and all additions reviewed.'\n",
        "severity": "Low",
        "enabled": true,
        "query": "(union isfuzzy=true\n(SecurityEvent\n| where EventID == 4720\n| where AccountType == \"User\"\n| project CreatedUserTime = TimeGenerated, CreatedUserEventID = EventID, CreatedUserActivity = Activity, Computer = toupper(Computer), \nCreatedUser = tolower(TargetAccount), CreatedUserSid = TargetSid, AccountUsedToCreateUser = strcat(SubjectAccount), SidofAccountUsedToCreateUser = SubjectUserSid\n),\n(WindowsEvent\n| where EventID == 4720\n| extend SubjectUserSid = tostring(EventData.SubjectUserSid)\n| extend AccountType=case(EventData.SubjectUserName endswith \"$\" or SubjectUserSid in (\"S-1-5-18\", \"S-1-5-19\", \"S-1-5-20\"), \"Machine\", isempty(SubjectUserSid), \"\", \"User\")\n| where AccountType == \"User\"\n| extend SubjectAccount = strcat(tostring(EventData.SubjectDomainName),\"\\\\\", tostring(EventData.SubjectUserName))\n| extend TargetAccount = strcat(EventData.TargetDomainName,\"\\\\\", EventData.TargetUserName)\n| extend Activity=\"4720 - A user account was created.\"\n| extend TargetSid = tostring(EventData.TargetSid)\n| project CreatedUserTime = TimeGenerated, CreatedUserEventID = EventID, CreatedUserActivity = Activity, Computer = toupper(Computer), \nCreatedUser = tolower(TargetAccount), CreatedUserSid = TargetSid, AccountUsedToCreateUser = strcat(SubjectAccount), SidofAccountUsedToCreateUser = SubjectUserSid\n))\n| join ((union isfuzzy=true\n(SecurityEvent \n| where AccountType == \"User\"\n// 4732 - A member was added to a security-enabled local group\n| where EventID == 4732\n// TargetSid is the builin Admins group: S-1-5-32-544\n| where TargetSid == \"S-1-5-32-544\"\n| project GroupAddTime = TimeGenerated, GroupAddEventID = EventID, GroupAddActivity = Activity, Computer = toupper(Computer), GroupName = tolower(TargetAccount), \nGroupSid = TargetSid, AccountThatAddedUser = SubjectAccount, SIDofAccountThatAddedUser = SubjectUserSid, CreatedUserSid = MemberSid\n),\n(  WindowsEvent \n// 4732 - A member was added to a security-enabled local group\n| where EventID == 4732 and EventData has \"S-1-5-32-544\"\n//TargetSid is the builin Admins group: S-1-5-32-544\n| extend SubjectUserSid = tostring(EventData.SubjectUserSid)\n| extend AccountType=case(EventData.SubjectUserName endswith \"$\" or SubjectUserSid in (\"S-1-5-18\", \"S-1-5-19\", \"S-1-5-20\"), \"Machine\", isempty(SubjectUserSid), \"\", \"User\")\n| where AccountType == \"User\"\n| extend TargetSid = tostring(EventData.TargetSid)\n| where TargetSid == \"S-1-5-32-544\"\n| extend SubjectAccount = strcat(tostring(EventData.SubjectDomainName),\"\\\\\", tostring(EventData.SubjectUserName))\n| extend TargetAccount = strcat(EventData.TargetDomainName,\"\\\\\", EventData.TargetUserName)\n| extend Activity=\"4732 - A member was added to a security-enabled local group.\"\n| extend MemberSid = tostring(EventData.MemberSid)\n| project GroupAddTime = TimeGenerated, GroupAddEventID = EventID, GroupAddActivity = Activity, Computer = toupper(Computer), GroupName = tolower(TargetAccount), \nGroupSid = TargetSid, AccountThatAddedUser = SubjectAccount, SIDofAccountThatAddedUser = SubjectUserSid, CreatedUserSid = MemberSid)\n))\non CreatedUserSid\n//Create User first, then the add to the group.\n| project Computer, CreatedUserTime, CreatedUserEventID, CreatedUserActivity, CreatedUser, CreatedUserSid, GroupAddTime, GroupAddEventID, \nGroupAddActivity, AccountUsedToCreateUser, GroupName, GroupSid, AccountThatAddedUser, SIDofAccountThatAddedUser \n| extend timestamp = CreatedUserTime, AccountCustomEntity = CreatedUser, HostCustomEntity = Computer\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Persistence",
          "PrivilegeEscalation"
        ],
        "techniques": [
          "T1098",
          "T1078"
        ],
        "alertRuleTemplateName": "aa1eff90-29d4-49dc-a3ea-b65199f516db",
        "customDetails": null,
        "entityMappings": [
          {
            "fieldMappings": [
              {
                "columnName": "AccountCustomEntity",
                "identifier": "FullName"
              },
              {
                "columnName": "CreatedUserSid",
                "identifier": "Sid"
              }
            ],
            "entityType": "Account"
          },
          {
            "fieldMappings": [
              {
                "columnName": "HostCustomEntity",
                "identifier": "FullName"
              }
            ],
            "entityType": "Host"
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/UserCreatedAddedToBuiltinAdmins_1d.yaml",
        "templateVersion": "1.1.3"
      }
    }
  ]
}