ESXi Shell Access Enabled

Description

This detection identifies when the ESXi Shell is enabled on a host, which may indicate that a malicious actor is preparing to execute commands locally or establish persistent access. Enabling the shell outside of approved maintenance windows can be a sign of compromise or unauthorized administrative activity.

Query · spl

`esxi_syslog` Message="*ESXi Shell*" Message="*has been enabled*" | rex field=_raw "'(?<user>\w+)@" | rex field=_raw "Z (?<dest>[\w\.]+)\s" | stats min(_time) as firstTime max(_time) as lastTime count by dest user Message | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `esxi_shell_access_enabled_filter`

Implementation guide

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. Some Administrators may enable this for troubleshooting.

Analyst notes

Known false positives: Limited false positives in most environments, however tune as needed. Some Administrators may enable this for troubleshooting.

Raw source ESXi Shell Access Enabled · SPL
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Published by splunk/security_content ↗, licensed under Apache 2.0 ↗. Reproduced here unmodified. 
name: ESXi Shell Access Enabled
id: 15e79d0a-c659-42fd-9668-94108528f2ec
version: 4
creation_date: '2025-07-11'
modification_date: '2026-05-13'
author: Raven Tait, Splunk
status: production
type: TTP
description: This detection identifies when the ESXi Shell is enabled on a host, which may indicate that a malicious actor is preparing to execute commands locally or establish persistent access. Enabling the shell outside of approved maintenance windows can be a sign of compromise or unauthorized administrative activity.
data_source:
    - VMWare ESXi Syslog
search: '`esxi_syslog` Message="*ESXi Shell*" Message="*has been enabled*" | rex field=_raw "''(?<user>\w+)@" | rex field=_raw "Z (?<dest>[\w\.]+)\s" | stats min(_time) as firstTime max(_time) as lastTime count by dest user Message | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `esxi_shell_access_enabled_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: Limited false positives in most environments, however tune as needed. Some Administrators may enable this for troubleshooting.
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: ESXi Shell access was enabled on ESXi host $dest$.
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - ESXi Post Compromise
    - Black Basta Ransomware
asset_type: Infrastructure
mitre_attack_id:
    - T1021
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/T1021/esxi_shell_enabled/esxi_shell_enabled.log
          source: vmware:esxlog
          sourcetype: vmw-syslog
      test_type: unit

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