First access credential added to Application or Service Principal where no credential was present

AuditLogs
| where OperationName has ("Certificates and secrets management")
| where Result =~ "success"
| where tostring(InitiatedBy.user.userPrincipalName) has "@" or tostring(InitiatedBy.app.displayName) has "@"
| mv-apply TargetResource = TargetResources on 
  (
      where TargetResource.type =~ "Application"
      | extend targetDisplayName = tostring(TargetResource.displayName),
               targetId = tostring(TargetResource.id),
               targetType = tostring(TargetResource.type),
               keyEvents = TargetResource.modifiedProperties
  )
| mv-apply Property = keyEvents on 
  (
      where Property.displayName =~ "KeyDescription"
      | extend new_value_set = parse_json(tostring(Property.newValue)),
               old_value_set = parse_json(tostring(Property.oldValue))
  )
| where old_value_set == "[]"  
| mv-expand new_value_set
| parse new_value_set with * "KeyIdentifier=" keyIdentifier:string ",KeyType=" keyType:string ",KeyUsage=" keyUsage:string ",DisplayName=" keyDisplayName:string "]" *
| where keyUsage =~ "Verify"
| mv-apply AdditionalDetail = AdditionalDetails on 
  (
      where AdditionalDetail.key =~ "User-Agent"
      | extend UserAgent = tostring(AdditionalDetail.value)
  )
| extend InitiatingUserOrApp = iff(isnotempty(InitiatedBy.user.userPrincipalName),tostring(InitiatedBy.user.userPrincipalName), tostring(InitiatedBy.app.displayName))
| extend InitiatingIpAddress = iff(isnotempty(InitiatedBy.user.ipAddress), tostring(InitiatedBy.user.ipAddress), tostring(InitiatedBy.app.ipAddress))
| project-away new_value_set, old_value_set
| project-reorder TimeGenerated, OperationName, InitiatingUserOrApp, InitiatingIpAddress, UserAgent, targetDisplayName, targetId, targetType, keyDisplayName, keyType, keyUsage, keyIdentifier, CorrelationId, TenantId
| extend timestamp = TimeGenerated, Name = tostring(split(InitiatingUserOrApp,'@',0)[0]), UPNSuffix = tostring(split(InitiatingUserOrApp,'@',1)[0])

severity: High
name: First access credential added to Application or Service Principal where no credential was present
requiredDataConnectors:
- dataTypes:
  - AuditLogs
  connectorId: AzureActiveDirectory
tags:
- Solorigate
- NOBELIUM
id: 2cfc3c6e-f424-4b88-9cc9-c89f482d016a
tactics:
- DefenseEvasion
queryFrequency: 1h
triggerOperator: gt
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Azure Active Directory/Analytic Rules/FirstAppOrServicePrincipalCredential.yaml
description: |
  'This will alert when an admin or app owner account adds a new credential to an Application or Service Principal where there was no previous verify KeyCredential associated.
  If a threat actor obtains access to an account with sufficient privileges and adds the alternate authentication material triggering this event, the threat actor can now authenticate as the Application or Service Principal using this credential.
  Additional information on OAuth Credential Grants can be found in RFC 6749 Section 4.4 or https://docs.microsoft.com/azure/active-directory/develop/v2-oauth2-client-creds-grant-flow
  For further information on AuditLogs please see https://docs.microsoft.com/azure/active-directory/reports-monitoring/reference-audit-activities.'  
triggerThreshold: 0
kind: Scheduled
relevantTechniques:
- T1550.001
query: |
  AuditLogs
  | where OperationName has ("Certificates and secrets management")
  | where Result =~ "success"
  | where tostring(InitiatedBy.user.userPrincipalName) has "@" or tostring(InitiatedBy.app.displayName) has "@"
  | mv-apply TargetResource = TargetResources on 
    (
        where TargetResource.type =~ "Application"
        | extend targetDisplayName = tostring(TargetResource.displayName),
                 targetId = tostring(TargetResource.id),
                 targetType = tostring(TargetResource.type),
                 keyEvents = TargetResource.modifiedProperties
    )
  | mv-apply Property = keyEvents on 
    (
        where Property.displayName =~ "KeyDescription"
        | extend new_value_set = parse_json(tostring(Property.newValue)),
                 old_value_set = parse_json(tostring(Property.oldValue))
    )
  | where old_value_set == "[]"  
  | mv-expand new_value_set
  | parse new_value_set with * "KeyIdentifier=" keyIdentifier:string ",KeyType=" keyType:string ",KeyUsage=" keyUsage:string ",DisplayName=" keyDisplayName:string "]" *
  | where keyUsage =~ "Verify"
  | mv-apply AdditionalDetail = AdditionalDetails on 
    (
        where AdditionalDetail.key =~ "User-Agent"
        | extend UserAgent = tostring(AdditionalDetail.value)
    )
  | extend InitiatingUserOrApp = iff(isnotempty(InitiatedBy.user.userPrincipalName),tostring(InitiatedBy.user.userPrincipalName), tostring(InitiatedBy.app.displayName))
  | extend InitiatingIpAddress = iff(isnotempty(InitiatedBy.user.ipAddress), tostring(InitiatedBy.user.ipAddress), tostring(InitiatedBy.app.ipAddress))
  | project-away new_value_set, old_value_set
  | project-reorder TimeGenerated, OperationName, InitiatingUserOrApp, InitiatingIpAddress, UserAgent, targetDisplayName, targetId, targetType, keyDisplayName, keyType, keyUsage, keyIdentifier, CorrelationId, TenantId
  | extend timestamp = TimeGenerated, Name = tostring(split(InitiatingUserOrApp,'@',0)[0]), UPNSuffix = tostring(split(InitiatingUserOrApp,'@',1)[0])  
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: Name
    identifier: Name
  - columnName: UPNSuffix
    identifier: UPNSuffix
- entityType: IP
  fieldMappings:
  - columnName: InitiatingIpAddress
    identifier: Address
- entityType: CloudApplication
  fieldMappings:
  - columnName: targetDisplayName
    identifier: Name
status: Available
version: 1.1.4
queryPeriod: 1h

{
  "$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/2cfc3c6e-f424-4b88-9cc9-c89f482d016a')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/2cfc3c6e-f424-4b88-9cc9-c89f482d016a')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01-preview",
      "properties": {
        "displayName": "First access credential added to Application or Service Principal where no credential was present",
        "description": "'This will alert when an admin or app owner account adds a new credential to an Application or Service Principal where there was no previous verify KeyCredential associated.\nIf a threat actor obtains access to an account with sufficient privileges and adds the alternate authentication material triggering this event, the threat actor can now authenticate as the Application or Service Principal using this credential.\nAdditional information on OAuth Credential Grants can be found in RFC 6749 Section 4.4 or https://docs.microsoft.com/azure/active-directory/develop/v2-oauth2-client-creds-grant-flow\nFor further information on AuditLogs please see https://docs.microsoft.com/azure/active-directory/reports-monitoring/reference-audit-activities.'\n",
        "severity": "High",
        "enabled": true,
        "query": "AuditLogs\n| where OperationName has (\"Certificates and secrets management\")\n| where Result =~ \"success\"\n| where tostring(InitiatedBy.user.userPrincipalName) has \"@\" or tostring(InitiatedBy.app.displayName) has \"@\"\n| mv-apply TargetResource = TargetResources on \n  (\n      where TargetResource.type =~ \"Application\"\n      | extend targetDisplayName = tostring(TargetResource.displayName),\n               targetId = tostring(TargetResource.id),\n               targetType = tostring(TargetResource.type),\n               keyEvents = TargetResource.modifiedProperties\n  )\n| mv-apply Property = keyEvents on \n  (\n      where Property.displayName =~ \"KeyDescription\"\n      | extend new_value_set = parse_json(tostring(Property.newValue)),\n               old_value_set = parse_json(tostring(Property.oldValue))\n  )\n| where old_value_set == \"[]\"  \n| mv-expand new_value_set\n| parse new_value_set with * \"KeyIdentifier=\" keyIdentifier:string \",KeyType=\" keyType:string \",KeyUsage=\" keyUsage:string \",DisplayName=\" keyDisplayName:string \"]\" *\n| where keyUsage =~ \"Verify\"\n| mv-apply AdditionalDetail = AdditionalDetails on \n  (\n      where AdditionalDetail.key =~ \"User-Agent\"\n      | extend UserAgent = tostring(AdditionalDetail.value)\n  )\n| extend InitiatingUserOrApp = iff(isnotempty(InitiatedBy.user.userPrincipalName),tostring(InitiatedBy.user.userPrincipalName), tostring(InitiatedBy.app.displayName))\n| extend InitiatingIpAddress = iff(isnotempty(InitiatedBy.user.ipAddress), tostring(InitiatedBy.user.ipAddress), tostring(InitiatedBy.app.ipAddress))\n| project-away new_value_set, old_value_set\n| project-reorder TimeGenerated, OperationName, InitiatingUserOrApp, InitiatingIpAddress, UserAgent, targetDisplayName, targetId, targetType, keyDisplayName, keyType, keyUsage, keyIdentifier, CorrelationId, TenantId\n| extend timestamp = TimeGenerated, Name = tostring(split(InitiatingUserOrApp,'@',0)[0]), UPNSuffix = tostring(split(InitiatingUserOrApp,'@',1)[0])\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "techniques": [
          "T1550.001"
        ],
        "alertRuleTemplateName": "2cfc3c6e-f424-4b88-9cc9-c89f482d016a",
        "customDetails": null,
        "entityMappings": [
          {
            "fieldMappings": [
              {
                "identifier": "Name",
                "columnName": "Name"
              },
              {
                "identifier": "UPNSuffix",
                "columnName": "UPNSuffix"
              }
            ],
            "entityType": "Account"
          },
          {
            "fieldMappings": [
              {
                "identifier": "Address",
                "columnName": "InitiatingIpAddress"
              }
            ],
            "entityType": "IP"
          },
          {
            "fieldMappings": [
              {
                "identifier": "Name",
                "columnName": "targetDisplayName"
              }
            ],
            "entityType": "CloudApplication"
          }
        ],
        "status": "Available",
        "templateVersion": "1.1.4",
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Azure Active Directory/Analytic Rules/FirstAppOrServicePrincipalCredential.yaml",
        "tags": [
          "Solorigate",
          "NOBELIUM"
        ]
      }
    }
  ]
}