Detection: ESXi VM Discovery

Updated Date: 2026-05-13 ID: 5643cdc9-a0be-4123-860b-f13da0bf4fcb Author: Raven Tait, Splunk Type: TTP Product: Splunk Enterprise Security

Description

This detection identifies the use of ESXCLI commands to discover virtual machines on an ESXi host While used by administrators, this activity may also indicate adversary reconnaissance aimed at identifying high value targets, mapping the virtual environment, or preparing for data theft or destructive operations.

Search

1`esxi_syslog` Message="*esxcli vm process*" Message="*list*" 
2| rex field=_raw "\]: \[(?<user>\w+)\]:(?<command>.+)" 
3| rex field=_raw "Z (?<dest>[\w\.]+)\s" 
4| stats min(_time) as firstTime max(_time) as lastTime count by dest user command 
5| `security_content_ctime(firstTime)` 
6| `security_content_ctime(lastTime)` 
7| `esxi_vm_discovery_filter`

Data Source

Name	Platform	Sourcetype	Source
VMWare ESXi Syslog	Other	`'vmw-syslog'`	`'vmware:esxlog'`

Macros Used

Name	Value
esxi_syslog	`sourcetype=vmw-syslog OR sourcetype=vmware:esxlog*`
esxi_vm_discovery_filter	`search *`

esxi_vm_discovery_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1673	Virtual Machine Discovery	Discovery

Exploitation

DE.CM

CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Finding (Notable)	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Intermediate Finding (Risk Event)	Yes

TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

Implementation

This is based on syslog data generated by VMware ESXi hosts. To implement this search, you must configure your ESXi systems to forward syslog output to your Splunk deployment. These logs must be ingested with the appropriate Splunk Technology Add-on for VMware ESXi Logs, which provides field extractions and CIM compatibility.

Known False Positives

Administrators may use this command when troubleshooting. Tune as needed.

Associated Analytic Story

Finding

Title	Entity Field	Entity Type	Risk Score
VM discovery commands executed on ESXi host $dest$ by $user$.	user	user	50

Intermediate Findings

Message	Entity Field	Entity Type	Risk Score
VM discovery commands executed on ESXi host $dest$ by $user$.	dest	system	50

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`vmware:esxlog`	`vmw-syslog`
Integration	✅ Passing	Dataset	`vmware:esxlog`	`vmw-syslog`

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 5