Detection rules › Splunk
ESXi Sensitive Files Accessed
This detection identifies access to sensitive system and configuration files on an ESXi host, including authentication data, service configurations, and VMware-specific management settings. Interaction with these files may indicate adversary reconnaissance, credential harvesting, or preparation for privilege escalation, lateral movement, or persistence.
Known false positives
- Administrators may access these files for initial setup or troubleshooting. Limited in most environments. Tune as needed.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Credential Access | |
| Collection |
Rule body
name: ESXi Sensitive Files Accessed
id: 6fa0073d-6ca0-4f93-913d-fb420c9de15b
version: 5
creation_date: '2025-07-11'
modification_date: '2026-05-13'
author: Raven Tait, Splunk
status: production
type: TTP
description: This detection identifies access to sensitive system and configuration files on an ESXi host, including authentication data, service configurations, and VMware-specific management settings. Interaction with these files may indicate adversary reconnaissance, credential harvesting, or preparation for privilege escalation, lateral movement, or persistence.
data_source:
- VMWare ESXi Syslog
search: '`esxi_syslog` Message="*shell[*" Message IN ("*/etc/shadow*","*/etc/vmware/hostd/hostd.xml*", "*/etc/vmware/vpxa/vpxa.cfg*","*/etc/sfcb/sfcb.cfg*","*/etc/security/*", "*/etc/likewise/krb5-affinity.conf*","*/etc/vmware-vpx/vcdb.properties*") | rex field=_raw "\]: \[(?<user>\w+)\]:(?<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_sensitive_files_accessed_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: Administrators may access these files for initial setup or troubleshooting. Limited in most environments. Tune as needed.
finding:
title: Sensitive files accessed on ESXi host $dest$ with $command$.
entity:
field: dest
type: system
score: 50
analytic_story:
- ESXi Post Compromise
- Black Basta Ransomware
- China-Nexus Threat Activity
asset_type: Infrastructure
mitre_attack_id:
- T1003.008
- T1005
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
category: application
security_domain: endpoint
Stages and Predicates
Stage 1: search
`esxi_syslog` Message="*shell[*" Message IN ("*/etc/shadow*","*/etc/vmware/hostd/hostd.xml*", "*/etc/vmware/vpxa/vpxa.cfg*","*/etc/sfcb/sfcb.cfg*","*/etc/security/*", "*/etc/likewise/krb5-affinity.conf*","*/etc/vmware-vpx/vcdb.properties*")
Stage 2: rex
| rex field=_raw "\]: \[(?<user>\w+)\]:(?<command>.+)"
Stage 3: rex
| rex field=_raw "Z (?<dest>[\w\.]+)\s"
Stage 4: stats
| stats min(_time) as firstTime max(_time) as lastTime count by dest user command
Stage 5: search
| `security_content_ctime(firstTime)`
Stage 6: search
| `security_content_ctime(lastTime)`
Stage 7: search
| `esxi_sensitive_files_accessed_filter`
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
Message | eq |
| field:"Message" kind:eq |
Message | in |
| field:"Message" kind:in |
sourcetype | in |
| field:"sourcetype" kind:in |