GitHub Repo

Detection: ESXi Audit Tampering

Updated Date: 2025-07-01 ID: c48a155b-2861-417a-813c-220f5272cf01 Author: Raven Tait, Splunk Type: TTP Product: Splunk Enterprise Security

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.

1`esxi_syslog` Message="*esxcli system auditrecords*" Message IN ("*remote*","*local*") NOT Message = "*[shell*" 
2| rex field=_raw "Z (?<dest>[\w\.]+)\s" 
3| rex field=_raw "[\w+]\]: (?<full_command>.*)" 
4| rex field=full_command "\[(?<user>.*)]:\s(?<command>.*)" 
5| stats min(_time) as firstTime max(_time) as lastTime count by dest user command 
6| `security_content_ctime(firstTime)` 
7| `security_content_ctime(lastTime)` 
8| `esxi_audit_tampering_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_audit_tampering_filter search *
esxi_audit_tampering_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
T1562.003 Impair Command History Logging Defense Evasion
T1070 Indicator Removal Defense Evasion
Exploitation
DE.CM
CIS 10

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:

Audit tampering activity on ESXi host $dest$.

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

References

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