Detection rules › Kusto
VMware ESXi - Multiple new VMs started
'Detects when multiple new VMs were started.'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access |
Rule body
id: bdea247f-7d17-498c-ac0e-c7e764cbdbbe
name: VMware ESXi - Multiple new VMs started
description: |
'Detects when multiple new VMs were started.'
severity: Medium
status: Available
requiredDataConnectors:
- connectorId: SyslogAma
datatypes:
- Syslog
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
- InitialAccess
relevantTechniques:
- T1078
query: |
let threshold = 5;
let a_vm =
VMwareESXi
| where SyslogMessage has ('VmPoweredOnEvent')
| extend DstHostname = extract(@'\[\d+\]\s+\[(.*?)\s+on', 1, SyslogMessage)
| summarize vm_l = make_set(DstHostname,200)
| extend k=1;
VMwareESXi
| where SyslogMessage has ('VmPoweredOnEvent')
| extend DstHostname = extract(@'\[\d+\]\s+\[(.*?)\s+on', 1, SyslogMessage)
| extend SrcUsername = extract(@'\[info\]\s+\[(.*?)\]', 1, SyslogMessage)
| extend k = 1
| join (a_vm) on k
| where vm_l !has DstHostname
| summarize n_vm = make_set(DstHostname,200) by SrcUsername, bin(TimeGenerated, 10m)
| where array_length(n_vm) >= threshold
| extend hostname = iff(array_length(n_vm) > 0, n_vm[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
Parameters
let threshold = 5;
Let binding: a_vm
let a_vm = VMwareESXi
| where SyslogMessage has ('VmPoweredOnEvent')
| extend DstHostname = extract(@'\[\d+\]\s+\[(.*?)\s+on', 1, SyslogMessage)
| summarize vm_l = make_set(DstHostname,200)
| extend k=1;
Stage 1: source
VMwareESXi
Stage 2: where
| where SyslogMessage has ('VmPoweredOnEvent')
Stage 3: extend (3 consecutive steps)
| extend DstHostname = extract(@'\[\d+\]\s+\[(.*?)\s+on', 1, SyslogMessage)
| extend SrcUsername = extract(@'\[info\]\s+\[(.*?)\]', 1, SyslogMessage)
| extend k = 1
Stage 4: join
| join (a_vm) on k
Stage 5: where
| where vm_l !has DstHostname
Stage 6: summarize
| summarize n_vm = make_set(DstHostname,200) by SrcUsername, bin(TimeGenerated, 10m)
Stage 7: where
| where array_length(n_vm) >= threshold
Stage 8: extend
| extend hostname = iff(array_length(n_vm) > 0, n_vm[0], "")
hostname =if
n_vm > 0n_vm[0]else
""Stage 9: extend
| extend NTDomain = tostring(split(hostname, '\\', 1)[0]), HostName = tostring(split(hostname, '.', 0)[0])
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
SyslogMessage | match |
| field:"SyslogMessage" kind:match value:"VmPoweredOnEvent" |
vm_l | cross_field_compare |
| field:"vm_l" kind:cross_field_compare value:"DstHostname" |
Output fields
These fields are emitted when the rule matches.
| Field | Source |
|---|---|
SrcUsername | summarize |
n_vm | summarize |
hostname | extend |
HostName | extend |
NTDomain | extend |