ESXi Bulk VM Termination

name: ESXi Bulk VM Termination
id: cfe094b4-0737-4a33-9d63-e0562ce2b883
version: 5
creation_date: '2025-07-11'
modification_date: '2026-09-08'
author: Raven Tait, Splunk
status: production
type: TTP
description: |-
    The following analytic detects when all virtual machines on an ESXi host are abruptly terminated, which may indicate malicious activity such as a deliberate denial-of-service, ransomware staging, or an attempt to destroy critical workloads.
data_source:
    - VMWare ESXi Syslog
search: |-
    `esxi_syslog`
    Message IN (
        "*pkill -9 *",
        "*process kill*"
    )
    | rex field=_raw "\s\[(?<user>[^\]]+)\]:\s(?<shell_command>.+)$"
    | rex field=_raw "Z (?<dest>[\w\.]+)\s.*:\s(?<esxicli_Command>esxcli\s.+)"
    | eval command=mvappend(esxicli_Command, shell_Command)
    | where isnotnull(command)
    | search (command="pkill -9 vmx-*")
             OR
             (
                command="*esxcli*"
                command="*--format-param*"
                command="*vm process list*"
                command="*awk*"
                command="*esxcli vm process kill*"
            )
    | stats min(_time) as firstTime
            max(_time) as lastTime
            values(_time) as timeStamp
            values(command) as commands

      by dest user

    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `esxi_bulk_vm_termination_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: No false positives have been identified at this time.
references:
    - https://www.securityweek.com/microsoft-says-ransomware-gangs-exploiting-just-patched-vmware-esxi-flaw/
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: Bulk VM termination activity on ESXi host [$dest$].
    entity:
        field: dest
        type: system
        score: 50
threat_objects: []
analytic_story:
    - ESXi Post Compromise
    - Black Basta Ransomware
asset_type: Infrastructure
mitre_attack_id:
    - T1673
    - T1529
    - T1499
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/T1529/esxi_bulk_vm_termination/esxi_bulk_vm_termination.log
          source: vmware:esxlog
          sourcetype: vmw-syslog
      test_type: unit