VMware ESXi - Dormant VM started

let vm_p_off =
VMwareESXi
| where TimeGenerated > ago(14d)
| where SyslogMessage has ('VmPoweredOffEvent')
| extend DstHostname = extract(@'\[\d+\]\s+\[(.*?)\s+on', 1, SyslogMessage)
| summarize LastPowerOffTime=max(TimeGenerated) by DstHostname
| where datetime_diff('day',datetime(now),LastPowerOffTime) >= 20; 
let vm_p_on =
VMwareESXi
| where TimeGenerated > ago(14d)
| where SyslogMessage has ('VmPoweredOnEvent')
| extend DstHostname = extract(@'\[\d+\]\s+\[(.*?)\s+on', 1, SyslogMessage)
| summarize LastPowerOnTime=max(TimeGenerated) by DstHostname
| where datetime_diff('day',datetime(now),LastPowerOnTime) >= 20;
let off_vms =
vm_p_on
| join (vm_p_off) on DstHostname
| where LastPowerOffTime > LastPowerOnTime
| summarize p_off_vm = make_set(DstHostname,200)
| extend k=1;
VMwareESXi
| where TimeGenerated between (ago(24h) .. datetime(now))
| where SyslogMessage has ('VmPoweredOnEvent')
| extend DstHostname = extract(@'\[\d+\]\s+\[(.*?)\s+on', 1, SyslogMessage)
| extend k=1
| join (off_vms) on k
| where p_off_vm !has DstHostname
| summarize rec_p_on = make_set(DstHostname,200)
| extend hostname = iff(array_length(rec_p_on) > 0, rec_p_on[0], "")
| extend NTDomain = tostring(split(hostname, '\\', 1)[0]), HostName = tostring(split(hostname, '.', 0)[0])

kind: Scheduled
id: 4cdcd5d8-89df-4076-a917-bc50abb9f2ab
entityMappings:
- fieldMappings:
  - identifier: HostName
    columnName: HostName
  - identifier: NTDomain
    columnName: NTDomain
  entityType: Host
name: VMware ESXi - Dormant VM started
severity: Medium
triggerOperator: gt
tactics:
- InitialAccess
query: |
  let vm_p_off =
  VMwareESXi
  | where TimeGenerated > ago(14d)
  | where SyslogMessage has ('VmPoweredOffEvent')
  | extend DstHostname = extract(@'\[\d+\]\s+\[(.*?)\s+on', 1, SyslogMessage)
  | summarize LastPowerOffTime=max(TimeGenerated) by DstHostname
  | where datetime_diff('day',datetime(now),LastPowerOffTime) >= 20; 
  let vm_p_on =
  VMwareESXi
  | where TimeGenerated > ago(14d)
  | where SyslogMessage has ('VmPoweredOnEvent')
  | extend DstHostname = extract(@'\[\d+\]\s+\[(.*?)\s+on', 1, SyslogMessage)
  | summarize LastPowerOnTime=max(TimeGenerated) by DstHostname
  | where datetime_diff('day',datetime(now),LastPowerOnTime) >= 20;
  let off_vms =
  vm_p_on
  | join (vm_p_off) on DstHostname
  | where LastPowerOffTime > LastPowerOnTime
  | summarize p_off_vm = make_set(DstHostname,200)
  | extend k=1;
  VMwareESXi
  | where TimeGenerated between (ago(24h) .. datetime(now))
  | where SyslogMessage has ('VmPoweredOnEvent')
  | extend DstHostname = extract(@'\[\d+\]\s+\[(.*?)\s+on', 1, SyslogMessage)
  | extend k=1
  | join (off_vms) on k
  | where p_off_vm !has DstHostname
  | summarize rec_p_on = make_set(DstHostname,200)
  | extend hostname = iff(array_length(rec_p_on) > 0, rec_p_on[0], "")
  | extend NTDomain = tostring(split(hostname, '\\', 1)[0]), HostName = tostring(split(hostname, '.', 0)[0])  
triggerThreshold: 0
description: |
    'Detects when dormant VM was started.'
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/VMWareESXi/Analytic Rules/ESXiDormantVMStarted.yaml
queryFrequency: 1h
queryPeriod: 14d
relevantTechniques:
- T1190
requiredDataConnectors:
- connectorId: SyslogAma
  datatypes:
  - Syslog
version: 1.0.3

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/4cdcd5d8-89df-4076-a917-bc50abb9f2ab')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/4cdcd5d8-89df-4076-a917-bc50abb9f2ab')]",
      "properties": {
        "alertRuleTemplateName": "4cdcd5d8-89df-4076-a917-bc50abb9f2ab",
        "customDetails": null,
        "description": "'Detects when dormant VM was started.'\n",
        "displayName": "VMware ESXi - Dormant VM started",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "NTDomain",
                "identifier": "NTDomain"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/VMWareESXi/Analytic Rules/ESXiDormantVMStarted.yaml",
        "query": "let vm_p_off =\nVMwareESXi\n| where TimeGenerated > ago(14d)\n| where SyslogMessage has ('VmPoweredOffEvent')\n| extend DstHostname = extract(@'\\[\\d+\\]\\s+\\[(.*?)\\s+on', 1, SyslogMessage)\n| summarize LastPowerOffTime=max(TimeGenerated) by DstHostname\n| where datetime_diff('day',datetime(now),LastPowerOffTime) >= 20; \nlet vm_p_on =\nVMwareESXi\n| where TimeGenerated > ago(14d)\n| where SyslogMessage has ('VmPoweredOnEvent')\n| extend DstHostname = extract(@'\\[\\d+\\]\\s+\\[(.*?)\\s+on', 1, SyslogMessage)\n| summarize LastPowerOnTime=max(TimeGenerated) by DstHostname\n| where datetime_diff('day',datetime(now),LastPowerOnTime) >= 20;\nlet off_vms =\nvm_p_on\n| join (vm_p_off) on DstHostname\n| where LastPowerOffTime > LastPowerOnTime\n| summarize p_off_vm = make_set(DstHostname,200)\n| extend k=1;\nVMwareESXi\n| where TimeGenerated between (ago(24h) .. datetime(now))\n| where SyslogMessage has ('VmPoweredOnEvent')\n| extend DstHostname = extract(@'\\[\\d+\\]\\s+\\[(.*?)\\s+on', 1, SyslogMessage)\n| extend k=1\n| join (off_vms) on k\n| where p_off_vm !has DstHostname\n| summarize rec_p_on = make_set(DstHostname,200)\n| extend hostname = iff(array_length(rec_p_on) > 0, rec_p_on[0], \"\")\n| extend NTDomain = tostring(split(hostname, '\\\\', 1)[0]), HostName = tostring(split(hostname, '.', 0)[0])\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1190"
        ],
        "templateVersion": "1.0.3",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}