ESXi Audit Tampering

SPLUNK detection rule by Raven Tait, Splunk · Apache-2.0

This detection identifies the use of the esxcli system auditrecords commands, which can be used to tamper with logging on an ESXi host. This action may indicate an attempt to evade detection or hinder forensic analysis by preventing the recording of system-level audit events.

name: ESXi Audit Tampering
id: c48a155b-2861-417a-813c-220f5272cf01
version: 5
creation_date: '2025-07-11'
modification_date: '2026-05-13'
author: Raven Tait, Splunk
status: production
type: TTP
description: This detection identifies the use of the esxcli system auditrecords commands, which can be used to tamper with logging on an ESXi host. This action may indicate an attempt to evade detection or hinder forensic analysis by preventing the recording of system-level audit events.
data_source:
    - VMWare ESXi Syslog
search: '`esxi_syslog` Message="*esxcli system auditrecords*" Message IN ("*remote*","*local*") NOT Message = "*[shell*" | rex field=_raw "Z (?<dest>[\w\.]+)\s" | rex field=_raw "[\w+]\]: (?<full_command>.*)" | rex field=full_command "\[(?<user>.*)]:\s(?<command>.*)" | stats min(_time) as firstTime max(_time) as lastTime count by dest user command | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `esxi_audit_tampering_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.
references:
    - https://detect.fyi/detecting-and-responding-to-esxi-compromise-with-splunk-f33998ce7823
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: Audit tampering activity 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
    - T1070
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/T1562.003/esxi_audit_tampering/esxi_audit_tampering.log
          source: vmware:esxlog
          sourcetype: vmw-syslog
      test_type: unit

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