Name:ESXi Account Modified id:b5e3b024-a7bb-4019-8975-46cf54485e78 version:1 date:2025-07-01 author:Raven Tait, Splunk status:production type:Anomaly Description:This detection identifies the creation, deletion, or modification of a local user account on an ESXi host. This activity may indicate unauthorized access, indicator removal, or persistence attempts by an attacker seeking to establish or maintain control of the host. Data_source:
-VMWare ESXi Syslog
search:`esxi_syslog` Message="*esxcli system account*" Message IN ("*-i *","*--id*") NOT Message="*[shell*" | rex field=_raw "Z (?<dest>[\w\.]+)\s.*: \[(?<initial_user>\w+)]:\s.+-i[d]*\s(?<modified_user>[\w_\-0-9]+)" | stats min(_time) as firstTime max(_time) as lastTime count by dest initial_user modified_user | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `esxi_account_modified_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:New local accounts being created in ESXi is rare in most environments. 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 ("$dest$") 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: - 'T1136.001' - 'T1078' - 'T1098' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' security_domain:endpoint
