Detection: ESXi Bulk VM Termination

Updated Date: 2025-05-12 ID: cfe094b4-0737-4a33-9d63-e0562ce2b883 Author: Raven Tait, Splunk Type: TTP Product: Splunk Enterprise Security

Description

This detection identifies 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.

Search

 1`esxi_syslog` 
 2| rex field=_raw "\s\[(?<user>[^\]]+)\]:\s(?<shell_command>.+)$" 
 3| rex field=_raw "Z (?<dest>[\w\.]+)\s.*:\s(?<esxicli_Command>esxcli\s.+)" 
 4| eval command=mvappend(esxicli_Command, shell_Command) 
 5| where isnotnull(command) 
 6| search (command="pkill -9 vmx-*") OR ( command="*esxcli*" AND command="*--format-param*" AND command="*vm process list*" AND command="*awk*" AND command="*esxcli vm process kill*") 
 7| stats min(_time) as firstTime max(_time) as lastTime values(_time) as timeStamp values(command) as commands values(user) as user by dest 
 8| `security_content_ctime(firstTime)` 
 9| `security_content_ctime(lastTime)` 
10| `esxi_bulk_vm_termination_filter`

Data Source

Name	Platform	Sourcetype	Source
VMWare ESXi Syslog	N/A	`'vmw-syslog'`	`'vmware:esxlog'`

Macros Used

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

esxi_bulk_vm_termination_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
T1529	System Shutdown/Reboot	Impact
T1499	Endpoint Denial of Service	Impact

Actions on Objectives

Exploitation

DE.CM

CIS 10

APT38

Lazarus Group

Sandworm Team

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 Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

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

Limited false positives in most environments, however tune as needed.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

Bulk VM termination activity on ESXi host $dest$.

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	50	No Threat Objects

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: 1