VMware ESXi - Dormant VM started

Severity: medium
Time window: 14d
Source: github.com/Azure/Azure-Sentinel

'Detects when dormant VM was started.'

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1190` Exploit Public-Facing Application

Rule body kusto

id: 4cdcd5d8-89df-4076-a917-bc50abb9f2ab
name: VMware ESXi - Dormant VM started
description: |
  'Detects when dormant VM was started.'
severity: Medium
requiredDataConnectors:
  - connectorId: SyslogAma
    datatypes:
      - Syslog
queryFrequency: 1h
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
relevantTechniques:
  - T1190
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])
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: HostName
      - identifier: NTDomain
        columnName: NTDomain
version: 1.0.3
kind: Scheduled

Stages and Predicates

Let binding: `vm_p_off`

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 binding: `vm_p_on`

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 binding: `off_vms`

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;

Derived from vm_p_off, vm_p_on.

Stage 1: `source`

VMwareESXi

Stage 2: `where`

| where TimeGenerated between (ago(24h) .. datetime(now))

Stage 3: `where`

| where SyslogMessage has ('VmPoweredOnEvent')

Stage 4: `extend`

| extend DstHostname = extract(@'\[\d+\]\s+\[(.*?)\s+on', 1, SyslogMessage)

Stage 5: `extend`

| extend k=1

Stage 6: `join`

| join (off_vms) on k

Stage 7: `where`

| where p_off_vm !has DstHostname

Stage 8: `summarize`

| summarize rec_p_on = make_set(DstHostname,200)

Stage 9: `extend`

| extend hostname = iff(array_length(rec_p_on) > 0, rec_p_on[0], "")

hostname =

ifrec_p_on > 0rec_p_on[0]

else""

Stage 10: `extend`

| extend NTDomain = tostring(split(hostname, '\\', 1)[0]), HostName = tostring(split(hostname, '.', 0)[0])

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`p_off_vm`	match	`DstHostname`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`LastPowerOffTime`	gt	`LastPowerOnTime` transforms: `cased`
`SyslogMessage`	match	`VmPoweredOffEvent` transforms: `term` `VmPoweredOnEvent` transforms: `term`

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field	Source
`rec_p_on`	`summarize`
`hostname`	`extend`
`HostName`	`extend`
`NTDomain`	`extend`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

VMware ESXi - Dormant VM started

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Let binding: `vm_p_off`

Let binding: `vm_p_on`

Let binding: `off_vms`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend`

Stage 5: `extend`

Stage 6: `join`

Stage 7: `where`

Stage 8: `summarize`

Stage 9: `extend`

Stage 10: `extend`

Exclusions

Indicators

Output fields

Keyboard shortcuts

Search operators

VMware ESXi - Dormant VM started

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Let binding: vm_p_off

Let binding: vm_p_on

Let binding: off_vms

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: extend

Stage 5: extend

Stage 6: join

Stage 7: where

Stage 8: summarize

Stage 9: extend

Stage 10: extend

Exclusions

Indicators

Output fields

Let binding: `vm_p_off`

Let binding: `vm_p_on`

Let binding: `off_vms`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend`

Stage 5: `extend`

Stage 6: `join`

Stage 7: `where`

Stage 8: `summarize`

Stage 9: `extend`

Stage 10: `extend`