ESXi VM Discovery

SPLUNK detection rule by Raven Tait, Splunk · Apache-2.0

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.

name: ESXi VM Discovery
id: 5643cdc9-a0be-4123-860b-f13da0bf4fcb
version: 5
creation_date: '2025-07-11'
modification_date: '2026-05-13'
author: Raven Tait, Splunk
status: production
type: TTP
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.
data_source:
    - VMWare ESXi Syslog
search: '`esxi_syslog` Message="*esxcli vm process*" Message="*list*" | rex field=_raw "\]: \[(?<user>\w+)\]:(?<command>.+)" | rex field=_raw "Z (?<dest>[\w\.]+)\s" | stats min(_time) as firstTime max(_time) as lastTime count by dest user command | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `esxi_vm_discovery_filter`'
how_to_implement: 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.
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: VM discovery commands executed on ESXi host $dest$ by $user$.
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: VM discovery commands executed on ESXi host $dest$ by $user$.
analytic_story:
    - ESXi Post Compromise
    - Black Basta Ransomware
    - China-Nexus Threat Activity
asset_type: Infrastructure
mitre_attack_id:
    - T1673
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: application
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1673/esxi_vm_discovery/esxi_vm_discovery.log
          source: vmware:esxlog
          sourcetype: vmw-syslog
      test_type: unit

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

102be7b9-fecb-4877-a574-29b4c8c2b393

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