ESXi Syslog Config Change

name: ESXi Syslog Config Change
id: e530beb9-9b8c-4c9b-9776-0a05521ff32d
version: 5
creation_date: '2025-07-11'
modification_date: '2026-05-13'
author: Raven Tait, Splunk
status: production
type: TTP
description: This detection identifies changes to the syslog configuration on an ESXi host using esxcli, which may indicate an attempt to disrupt log collection and evade detection.
data_source:
    - VMWare ESXi Syslog
search: '`esxi_syslog` Message="*syslog config set*" AND Message="*esxcli*" | rex field=_raw "\].*\[\s*(?P<user>[^\]]+)\]:\s(?P<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_syslog_config_change_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: Syslog config was 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:
    - T1690
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: application
security_domain: endpoint