Detection: ESXi Audit Tampering

Updated Date: 2026-09-08 ID: c48a155b-2861-417a-813c-220f5272cf01 Author: Raven Tait, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic 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.

Search

 1`esxi_syslog`
 2Message="*esxcli system auditrecords*"
 3Message IN ("*remote*","*local*")
 4NOT Message = "*[shell*"
 5
 6
 7| rex field=_raw "Z (?<dest>[\w\.]+)\s"
 8
 9| rex field=_raw "[\w+]\]: (?<full_command>.*)"
10
11| rex field=full_command "\[(?<user>.*)]:\s(?<command>.*)"
12
13
14| stats count min(_time) as firstTime
15              max(_time) as lastTime
16        by dest user command
17
18
19| `security_content_ctime(firstTime)`
20
21| `security_content_ctime(lastTime)`
22
23| `esxi_audit_tampering_filter`

Data Source

Name	Platform	Sourcetype	Source
VMWare ESXi Syslog	Other	`'vmw-syslog'`	`'vmware:esxlog'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
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
T1070	Indicator Removal	Stealth
T1690	Prevent Command History Logging	Defense Impairment

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 Finding (Notable)	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Intermediate Finding (Risk Event)	No

TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

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

No false positives have been identified at this time.

Associated Analytic Story

Finding

Title	Entity Field	Entity Type	Risk Score
Audit tampering activity via [$command$] on ESXi host [$dest$].	dest	system	50

Threat Objects

Field	Type
command	command

References

https://detect.fyi/detecting-and-responding-to-esxi-compromise-with-splunk-f33998ce7823

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: 6