Trend Micro CAS - Possible phishing mail

let threshold = 5;
TrendMicroCAS
| where EventCategoryType in~ ('exchange', 'gmail', 'exchangeserver')
| where isnotempty(SrcFileName)
| where isnotempty(SecurityRiskName)
| summarize r_users = makeset(DstUserName) by SrcFileName, bin(TimeGenerated, 30m)
| where array_length(r_users) > threshold
| extend AccountCustomEntity = r_users

triggerOperator: gt
queryFrequency: 1h
description: |
    'Detects possible phishing mail.'
status: Available
kind: Scheduled
triggerThreshold: 0
requiredDataConnectors:
- connectorId: TrendMicroCAS
  dataTypes:
  - TrendMicroCAS
version: 1.0.0
queryPeriod: 1h
name: Trend Micro CAS - Possible phishing mail
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Trend Micro Cloud App Security/Analytic Rules/TrendMicroCASPossiblePhishingMail.yaml
id: 9e7b3811-d743-479c-a296-635410562429
tactics:
- InitialAccess
relevantTechniques:
- T1566
severity: Medium
entityMappings:
- fieldMappings:
  - identifier: Name
    columnName: AccountCustomEntity
  entityType: Account
query: |
  let threshold = 5;
  TrendMicroCAS
  | where EventCategoryType in~ ('exchange', 'gmail', 'exchangeserver')
  | where isnotempty(SrcFileName)
  | where isnotempty(SecurityRiskName)
  | summarize r_users = makeset(DstUserName) by SrcFileName, bin(TimeGenerated, 30m)
  | where array_length(r_users) > threshold
  | extend AccountCustomEntity = r_users  

{
  "$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/9e7b3811-d743-479c-a296-635410562429')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/9e7b3811-d743-479c-a296-635410562429')]",
      "properties": {
        "alertRuleTemplateName": "9e7b3811-d743-479c-a296-635410562429",
        "customDetails": null,
        "description": "'Detects possible phishing mail.'\n",
        "displayName": "Trend Micro CAS - Possible phishing mail",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "AccountCustomEntity",
                "identifier": "Name"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Trend Micro Cloud App Security/Analytic Rules/TrendMicroCASPossiblePhishingMail.yaml",
        "query": "let threshold = 5;\nTrendMicroCAS\n| where EventCategoryType in~ ('exchange', 'gmail', 'exchangeserver')\n| where isnotempty(SrcFileName)\n| where isnotempty(SecurityRiskName)\n| summarize r_users = makeset(DstUserName) by SrcFileName, bin(TimeGenerated, 30m)\n| where array_length(r_users) > threshold\n| extend AccountCustomEntity = r_users\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Medium",
        "status": "Available",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1566"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}