Account added and removed from privileged groups

let WellKnownLocalSID = "S-1-5-32-5[0-9][0-9]$";
let WellKnownGroupSID = "S-1-5-21-[0-9]*-[0-9]*-[0-9]*-5[0-9][0-9]$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1102$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1103$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-498$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1000$";
let AC_Add =
(union isfuzzy=true
(SecurityEvent
// Event ID related to member addition.
| where EventID in (4728, 4732,4756)
| where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
| parse EventData with * '"MemberName">' * '=' AccountAdded ",OU" *
| where isnotempty(AccountAdded)
| extend GroupAddedTo = TargetUserName, AddingAccount = Account
| extend  AccountAdded_GroupAddedTo_AddingAccount = strcat(AccountAdded, "||", GroupAddedTo, "||", AddingAccount )
| project AccountAdded_GroupAddedTo_AddingAccount, AccountAddedTime = TimeGenerated
),
(WindowsEvent
// Event ID related to member addition.
| where EventID in (4728, 4732,4756)
| extend TargetSid = tostring(EventData.TargetSid)
| where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
| parse EventData.MemberName with * '"MemberName">' * '=' AccountAdded ",OU" *
| where isnotempty(AccountAdded)
| extend TargetUserName = tostring(EventData.TargetUserName)
| extend AddingAccount =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
| extend GroupAddedTo = TargetUserName
| extend  AccountAdded_GroupAddedTo_AddingAccount = strcat(AccountAdded, "||", GroupAddedTo, "||", AddingAccount )
| project AccountAdded_GroupAddedTo_AddingAccount, AccountAddedTime = TimeGenerated
)
);
let AC_Remove =
( union isfuzzy=true
(SecurityEvent
// Event IDs related to member removal.
| where EventID in (4729,4733,4757)
| where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
| parse EventData with * '"MemberName">' * '=' AccountRemoved ",OU" *
| where isnotempty(AccountRemoved)
| extend GroupRemovedFrom = TargetUserName, RemovingAccount = Account
| extend AccountRemoved_GroupRemovedFrom_RemovingAccount = strcat(AccountRemoved, "||", GroupRemovedFrom, "||", RemovingAccount)
| project AccountRemoved_GroupRemovedFrom_RemovingAccount, AccountRemovedTime = TimeGenerated, Computer, AccountRemoved = tolower(AccountRemoved),
RemovingAccount, RemovingAccountLogonId = SubjectLogonId, GroupRemovedFrom = TargetUserName, TargetDomainName
),
(WindowsEvent
// Event IDs related to member removal.
| where EventID in (4729,4733,4757)
| extend TargetSid = tostring(EventData.TargetSid)
| where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
| parse EventData.MemberName with * '"MemberName">' * '=' AccountRemoved ",OU" *
| where isnotempty(AccountRemoved)
| extend TargetUserName = tostring(EventData.TargetUserName)
| extend RemovingAccount =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
| extend GroupRemovedFrom = TargetUserName
| extend AccountRemoved_GroupRemovedFrom_RemovingAccount = strcat(AccountRemoved, "||", GroupRemovedFrom, "||", RemovingAccount)
| extend RemovedAccountLogonId= tostring(EventData.SubjectLogonId)
| extend TargetDomainName = tostring(EventData.TargetDomainName)
| project AccountRemoved_GroupRemovedFrom_RemovingAccount, AccountRemovedTime = TimeGenerated, Computer, AccountRemoved = tolower(AccountRemoved),
RemovingAccount, RemovedAccountLogonId, GroupRemovedFrom = TargetUserName, TargetDomainName
));
AC_Add
| join kind = inner AC_Remove 
on $left.AccountAdded_GroupAddedTo_AddingAccount == $right.AccountRemoved_GroupRemovedFrom_RemovingAccount
| extend DurationinSecondAfter_Removed = datetime_diff ('second', AccountRemovedTime, AccountAddedTime)
| where DurationinSecondAfter_Removed > 0
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| extend RemovedAccountName = tostring(split(AccountRemoved, @"\")[1]), RemovedAccountNTDomain = tostring(split(AccountRemoved, @"\")[0])
| extend RemovingAccountName = tostring(split(RemovingAccount, @"\")[1]), RemovingAccountNTDomain = tostring(split(RemovingAccount, @"\")[0])
| project-away DomainIndex

name: Account added and removed from privileged groups
id: 7efc75ce-e2a4-400f-a8b1-283d3b0f2c60
triggerThreshold: 0
severity: Low
tactics:
- Persistence
- PrivilegeEscalation
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/SecurityEvent/UserAccountAdd-Removed.yaml
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: AccountRemoved
    identifier: FullName
  - columnName: RemovedAccountName
    identifier: Name
  - columnName: RemovedAccountNTDomain
    identifier: NTDomain
- entityType: Account
  fieldMappings:
  - columnName: RemovingAccount
    identifier: FullName
  - columnName: RemovingAccountName
    identifier: Name
  - columnName: RemovingAccountNTDomain
    identifier: NTDomain
- entityType: Host
  fieldMappings:
  - columnName: Computer
    identifier: FullName
  - columnName: HostName
    identifier: HostName
  - columnName: HostNameDomain
    identifier: NTDomain
queryPeriod: 1d
queryFrequency: 1d
version: 1.1.5
triggerOperator: gt
description: |
    'Identifies accounts that are added to a privileged group and then quickly removed, which could be a sign of compromise.'
metadata:
  support:
    tier: Community
  author:
    name: Microsoft Security Research
  source:
    kind: Community
  categories:
    domains:
    - Security - Others
    - Identity
query: |
  let WellKnownLocalSID = "S-1-5-32-5[0-9][0-9]$";
  let WellKnownGroupSID = "S-1-5-21-[0-9]*-[0-9]*-[0-9]*-5[0-9][0-9]$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1102$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1103$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-498$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1000$";
  let AC_Add =
  (union isfuzzy=true
  (SecurityEvent
  // Event ID related to member addition.
  | where EventID in (4728, 4732,4756)
  | where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
  | parse EventData with * '"MemberName">' * '=' AccountAdded ",OU" *
  | where isnotempty(AccountAdded)
  | extend GroupAddedTo = TargetUserName, AddingAccount = Account
  | extend  AccountAdded_GroupAddedTo_AddingAccount = strcat(AccountAdded, "||", GroupAddedTo, "||", AddingAccount )
  | project AccountAdded_GroupAddedTo_AddingAccount, AccountAddedTime = TimeGenerated
  ),
  (WindowsEvent
  // Event ID related to member addition.
  | where EventID in (4728, 4732,4756)
  | extend TargetSid = tostring(EventData.TargetSid)
  | where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
  | parse EventData.MemberName with * '"MemberName">' * '=' AccountAdded ",OU" *
  | where isnotempty(AccountAdded)
  | extend TargetUserName = tostring(EventData.TargetUserName)
  | extend AddingAccount =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
  | extend GroupAddedTo = TargetUserName
  | extend  AccountAdded_GroupAddedTo_AddingAccount = strcat(AccountAdded, "||", GroupAddedTo, "||", AddingAccount )
  | project AccountAdded_GroupAddedTo_AddingAccount, AccountAddedTime = TimeGenerated
  )
  );
  let AC_Remove =
  ( union isfuzzy=true
  (SecurityEvent
  // Event IDs related to member removal.
  | where EventID in (4729,4733,4757)
  | where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
  | parse EventData with * '"MemberName">' * '=' AccountRemoved ",OU" *
  | where isnotempty(AccountRemoved)
  | extend GroupRemovedFrom = TargetUserName, RemovingAccount = Account
  | extend AccountRemoved_GroupRemovedFrom_RemovingAccount = strcat(AccountRemoved, "||", GroupRemovedFrom, "||", RemovingAccount)
  | project AccountRemoved_GroupRemovedFrom_RemovingAccount, AccountRemovedTime = TimeGenerated, Computer, AccountRemoved = tolower(AccountRemoved),
  RemovingAccount, RemovingAccountLogonId = SubjectLogonId, GroupRemovedFrom = TargetUserName, TargetDomainName
  ),
  (WindowsEvent
  // Event IDs related to member removal.
  | where EventID in (4729,4733,4757)
  | extend TargetSid = tostring(EventData.TargetSid)
  | where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID
  | parse EventData.MemberName with * '"MemberName">' * '=' AccountRemoved ",OU" *
  | where isnotempty(AccountRemoved)
  | extend TargetUserName = tostring(EventData.TargetUserName)
  | extend RemovingAccount =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
  | extend GroupRemovedFrom = TargetUserName
  | extend AccountRemoved_GroupRemovedFrom_RemovingAccount = strcat(AccountRemoved, "||", GroupRemovedFrom, "||", RemovingAccount)
  | extend RemovedAccountLogonId= tostring(EventData.SubjectLogonId)
  | extend TargetDomainName = tostring(EventData.TargetDomainName)
  | project AccountRemoved_GroupRemovedFrom_RemovingAccount, AccountRemovedTime = TimeGenerated, Computer, AccountRemoved = tolower(AccountRemoved),
  RemovingAccount, RemovedAccountLogonId, GroupRemovedFrom = TargetUserName, TargetDomainName
  ));
  AC_Add
  | join kind = inner AC_Remove 
  on $left.AccountAdded_GroupAddedTo_AddingAccount == $right.AccountRemoved_GroupRemovedFrom_RemovingAccount
  | extend DurationinSecondAfter_Removed = datetime_diff ('second', AccountRemovedTime, AccountAddedTime)
  | where DurationinSecondAfter_Removed > 0
  | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
  | extend RemovedAccountName = tostring(split(AccountRemoved, @"\")[1]), RemovedAccountNTDomain = tostring(split(AccountRemoved, @"\")[0])
  | extend RemovingAccountName = tostring(split(RemovingAccount, @"\")[1]), RemovingAccountNTDomain = tostring(split(RemovingAccount, @"\")[0])
  | project-away DomainIndex  
relevantTechniques:
- T1098
- T1078
requiredDataConnectors:
- dataTypes:
  - SecurityEvent
  connectorId: SecurityEvents
- dataTypes:
  - SecurityEvent
  connectorId: WindowsSecurityEvents
- dataTypes:
  - WindowsEvent
  connectorId: WindowsForwardedEvents
kind: Scheduled

{
  "$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/7efc75ce-e2a4-400f-a8b1-283d3b0f2c60')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/7efc75ce-e2a4-400f-a8b1-283d3b0f2c60')]",
      "properties": {
        "alertRuleTemplateName": "7efc75ce-e2a4-400f-a8b1-283d3b0f2c60",
        "customDetails": null,
        "description": "'Identifies accounts that are added to a privileged group and then quickly removed, which could be a sign of compromise.'\n",
        "displayName": "Account added and removed from privileged groups",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "AccountRemoved",
                "identifier": "FullName"
              },
              {
                "columnName": "RemovedAccountName",
                "identifier": "Name"
              },
              {
                "columnName": "RemovedAccountNTDomain",
                "identifier": "NTDomain"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "RemovingAccount",
                "identifier": "FullName"
              },
              {
                "columnName": "RemovingAccountName",
                "identifier": "Name"
              },
              {
                "columnName": "RemovingAccountNTDomain",
                "identifier": "NTDomain"
              }
            ]
          },
          {
            "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/UserAccountAdd-Removed.yaml",
        "query": "let WellKnownLocalSID = \"S-1-5-32-5[0-9][0-9]$\";\nlet WellKnownGroupSID = \"S-1-5-21-[0-9]*-[0-9]*-[0-9]*-5[0-9][0-9]$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1102$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1103$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-498$|S-1-5-21-[0-9]*-[0-9]*-[0-9]*-1000$\";\nlet AC_Add =\n(union isfuzzy=true\n(SecurityEvent\n// Event ID related to member addition.\n| where EventID in (4728, 4732,4756)\n| where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID\n| parse EventData with * '\"MemberName\">' * '=' AccountAdded \",OU\" *\n| where isnotempty(AccountAdded)\n| extend GroupAddedTo = TargetUserName, AddingAccount = Account\n| extend  AccountAdded_GroupAddedTo_AddingAccount = strcat(AccountAdded, \"||\", GroupAddedTo, \"||\", AddingAccount )\n| project AccountAdded_GroupAddedTo_AddingAccount, AccountAddedTime = TimeGenerated\n),\n(WindowsEvent\n// Event ID related to member addition.\n| where EventID in (4728, 4732,4756)\n| extend TargetSid = tostring(EventData.TargetSid)\n| where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID\n| parse EventData.MemberName with * '\"MemberName\">' * '=' AccountAdded \",OU\" *\n| where isnotempty(AccountAdded)\n| extend TargetUserName = tostring(EventData.TargetUserName)\n| extend AddingAccount =  strcat(tostring(EventData.SubjectDomainName),\"\\\\\", tostring(EventData.SubjectUserName))\n| extend GroupAddedTo = TargetUserName\n| extend  AccountAdded_GroupAddedTo_AddingAccount = strcat(AccountAdded, \"||\", GroupAddedTo, \"||\", AddingAccount )\n| project AccountAdded_GroupAddedTo_AddingAccount, AccountAddedTime = TimeGenerated\n)\n);\nlet AC_Remove =\n( union isfuzzy=true\n(SecurityEvent\n// Event IDs related to member removal.\n| where EventID in (4729,4733,4757)\n| where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID\n| parse EventData with * '\"MemberName\">' * '=' AccountRemoved \",OU\" *\n| where isnotempty(AccountRemoved)\n| extend GroupRemovedFrom = TargetUserName, RemovingAccount = Account\n| extend AccountRemoved_GroupRemovedFrom_RemovingAccount = strcat(AccountRemoved, \"||\", GroupRemovedFrom, \"||\", RemovingAccount)\n| project AccountRemoved_GroupRemovedFrom_RemovingAccount, AccountRemovedTime = TimeGenerated, Computer, AccountRemoved = tolower(AccountRemoved),\nRemovingAccount, RemovingAccountLogonId = SubjectLogonId, GroupRemovedFrom = TargetUserName, TargetDomainName\n),\n(WindowsEvent\n// Event IDs related to member removal.\n| where EventID in (4729,4733,4757)\n| extend TargetSid = tostring(EventData.TargetSid)\n| where TargetSid matches regex WellKnownLocalSID or TargetSid matches regex WellKnownGroupSID\n| parse EventData.MemberName with * '\"MemberName\">' * '=' AccountRemoved \",OU\" *\n| where isnotempty(AccountRemoved)\n| extend TargetUserName = tostring(EventData.TargetUserName)\n| extend RemovingAccount =  strcat(tostring(EventData.SubjectDomainName),\"\\\\\", tostring(EventData.SubjectUserName))\n| extend GroupRemovedFrom = TargetUserName\n| extend AccountRemoved_GroupRemovedFrom_RemovingAccount = strcat(AccountRemoved, \"||\", GroupRemovedFrom, \"||\", RemovingAccount)\n| extend RemovedAccountLogonId= tostring(EventData.SubjectLogonId)\n| extend TargetDomainName = tostring(EventData.TargetDomainName)\n| project AccountRemoved_GroupRemovedFrom_RemovingAccount, AccountRemovedTime = TimeGenerated, Computer, AccountRemoved = tolower(AccountRemoved),\nRemovingAccount, RemovedAccountLogonId, GroupRemovedFrom = TargetUserName, TargetDomainName\n));\nAC_Add\n| join kind = inner AC_Remove \non $left.AccountAdded_GroupAddedTo_AddingAccount == $right.AccountRemoved_GroupRemovedFrom_RemovingAccount\n| extend DurationinSecondAfter_Removed = datetime_diff ('second', AccountRemovedTime, AccountAddedTime)\n| where DurationinSecondAfter_Removed > 0\n| extend HostName = tostring(split(Computer, \".\")[0]), DomainIndex = toint(indexof(Computer, '.'))\n| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)\n| extend RemovedAccountName = tostring(split(AccountRemoved, @\"\\\")[1]), RemovedAccountNTDomain = tostring(split(AccountRemoved, @\"\\\")[0])\n| extend RemovingAccountName = tostring(split(RemovingAccount, @\"\\\")[1]), RemovingAccountNTDomain = tostring(split(RemovingAccount, @\"\\\")[0])\n| project-away DomainIndex\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "Low",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Persistence",
          "PrivilegeEscalation"
        ],
        "techniques": [
          "T1078",
          "T1098"
        ],
        "templateVersion": "1.1.5",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}