ESXi Encryption Settings Modified

name: ESXi Encryption Settings Modified
id: dbbbe26f-83fe-4ee3-8b77-ccf7fbd416c8
version: 5
creation_date: '2025-07-11'
modification_date: '2026-05-13'
author: Raven Tait, Splunk
status: production
type: TTP
description: Detects the disabling of critical encryption enforcement settings on an ESXi host, such as secure boot or executable verification requirements, which may indicate an attempt to weaken hypervisor integrity or allow unauthorized code execution.
data_source:
    - VMWare ESXi Syslog
search: '`esxi_syslog` Message="*system settings encryption set*" NOT Message="*shell.*" Message IN ("* -s *", "* -e *","*--require-secure-boot*", "*require-exec-installed-only*", "execInstalledOnly") | rex field=_raw "Z (?<dest>[\w\.]*)\s.*\]: \[(?<user>\w+)\]:(?<command>.+)" | stats min(_time) as firstTime max(_time) as lastTime count by dest user command | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `esxi_encryption_settings_modified_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.
finding:
    title: Encryption settings modified 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:
    - T1685
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: application
security_domain: endpoint