VMware ESXi - Unexpected disk image

let img_ =
VMwareESXi
| where SyslogMessage has ('Matched discovered VM')
| extend DstHostname = extract(@'vim.VirtualMachine\S+,(.*?)\]', 1, SyslogMessage)
| extend kImageName = extract(@'ds:///vmfs/volumes/(.*)/(.*?),', 2, SyslogMessage)
| summarize img_lst = makeset(kImageName) by DstHostname;
VMwareESXi
| where SyslogMessage has ('Matched discovered VM')
| extend DstHostname = extract(@'vim.VirtualMachine\S+,(.*?)\]', 1, SyslogMessage)
| extend ImageName = extract(@'ds:///vmfs/volumes/(.*)/(.*?),', 2, SyslogMessage)
| join (img_) on DstHostname
| where img_lst !has ImageName
| extend HostCustomEntity = DstHostname

version: 1.0.0
status: Available
queryFrequency: 1h
requiredDataConnectors:
- connectorId: VMwareESXi
  dataTypes:
  - VMwareESXi
entityMappings:
- fieldMappings:
  - columnName: HostCustomEntity
    identifier: FullName
  entityType: Host
kind: Scheduled
queryPeriod: 14d
severity: Medium
query: |
  let img_ =
  VMwareESXi
  | where SyslogMessage has ('Matched discovered VM')
  | extend DstHostname = extract(@'vim.VirtualMachine\S+,(.*?)\]', 1, SyslogMessage)
  | extend kImageName = extract(@'ds:///vmfs/volumes/(.*)/(.*?),', 2, SyslogMessage)
  | summarize img_lst = makeset(kImageName) by DstHostname;
  VMwareESXi
  | where SyslogMessage has ('Matched discovered VM')
  | extend DstHostname = extract(@'vim.VirtualMachine\S+,(.*?)\]', 1, SyslogMessage)
  | extend ImageName = extract(@'ds:///vmfs/volumes/(.*)/(.*?),', 2, SyslogMessage)
  | join (img_) on DstHostname
  | where img_lst !has ImageName
  | extend HostCustomEntity = DstHostname  
triggerOperator: gt
id: 395c5560-ddc2-45b2-aafe-2e3f64528d3d
description: |
    'Detects unexpected disk image for VM.'
triggerThreshold: 0
name: VMware ESXi - Unexpected disk image
relevantTechniques:
- T1496
tactics:
- Impact
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/VMWareESXi/Analytic Rules/ESXiUnexpectedDiskImage.yaml

{
  "$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/395c5560-ddc2-45b2-aafe-2e3f64528d3d')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/395c5560-ddc2-45b2-aafe-2e3f64528d3d')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "VMware ESXi - Unexpected disk image",
        "description": "'Detects unexpected disk image for VM.'\n",
        "severity": "Medium",
        "enabled": true,
        "query": "let img_ =\nVMwareESXi\n| where SyslogMessage has ('Matched discovered VM')\n| extend DstHostname = extract(@'vim.VirtualMachine\\S+,(.*?)\\]', 1, SyslogMessage)\n| extend kImageName = extract(@'ds:///vmfs/volumes/(.*)/(.*?),', 2, SyslogMessage)\n| summarize img_lst = makeset(kImageName) by DstHostname;\nVMwareESXi\n| where SyslogMessage has ('Matched discovered VM')\n| extend DstHostname = extract(@'vim.VirtualMachine\\S+,(.*?)\\]', 1, SyslogMessage)\n| extend ImageName = extract(@'ds:///vmfs/volumes/(.*)/(.*?),', 2, SyslogMessage)\n| join (img_) on DstHostname\n| where img_lst !has ImageName\n| extend HostCustomEntity = DstHostname\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Impact"
        ],
        "techniques": [
          "T1496"
        ],
        "alertRuleTemplateName": "395c5560-ddc2-45b2-aafe-2e3f64528d3d",
        "customDetails": null,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "identifier": "FullName",
                "columnName": "HostCustomEntity"
              }
            ]
          }
        ],
        "status": "Available",
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/VMWareESXi/Analytic Rules/ESXiUnexpectedDiskImage.yaml",
        "templateVersion": "1.0.0"
      }
    }
  ]
}