ESXi Syslog Config Change

Name:ESXi Syslog Config Change
id:e530beb9-9b8c-4c9b-9776-0a05521ff32d
version:1
date:2025-05-13
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
References:
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 ("$dest$") starthoursago=168 | 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:'$info_min_time$'
 latest_offset:'$info_max_time$'
tags:
  analytic_story:
    - 'ESXi Post Compromise'
    - 'Black Basta Ransomware'
  asset_type:Infrastructure
  mitre_attack_id:
    - 'T1562.003'
  product:
    - 'Splunk Enterprise'
    - 'Splunk Enterprise Security'
    - 'Splunk Cloud'
  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_syslog_config/esxi_syslog_config.log
  source: vmware:esxlog
  sourcetype: vmw-syslog
manual_test:None