Windows ESX Admins Group Creation via PowerShell

 Original Source: [splunk source]
Name:Windows ESX Admins Group Creation via PowerShell
id:f48a5557-be06-4b96-b8e8-be563e387620
version:10
date:None
author:Michael Haag, Splunk
status:production
type:TTP
Description:This analytic detects attempts to create an "ESX Admins" group using PowerShell commands. This activity may indicate an attempt to exploit the VMware ESXi Active Directory Integration Authentication Bypass vulnerability (CVE-2024-37085). Attackers can use this method to gain unauthorized access to ESXi hosts by recreating the 'ESX Admins' group after its deletion from Active Directory.
Data_source:
  • -Powershell Script Block Logging 4104
search:`powershell` EventCode=4104 (ScriptBlockText="*New-ADGroup*" OR ScriptBlockText="*New-LocalGroup*") ScriptBlockText="*ESX Admins*"

| fillnull

| stats count min(_time) as firstTime max(_time) as lastTime
BY dest signature signature_id
user_id vendor_product EventID
Guid Opcode Name
Path ProcessID ScriptBlockId
ScriptBlockText

| `security_content_ctime(firstTime)`

| `security_content_ctime(lastTime)`

| `windows_esx_admins_group_creation_via_powershell_filter`


how_to_implement:To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. You can find additional setup instructions in the Splunk documentation for configuring PowerShell logging.
known_false_positives:Legitimate administrators might create an "ESX Admins" group for valid reasons. Verify that the group creation is authorized and part of normal administrative tasks. Consider the context of the action, such as the user performing it and any related activities.
References:
  -https://support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/24505
  -https://www.microsoft.com/en-us/security/blog/2024/07/29/ransomware-operators-exploit-esxi-hypervisor-vulnerability-for-mass-encryption/
  -https://www.securityweek.com/microsoft-says-ransomware-gangs-exploiting-just-patched-vmware-esxi-flaw/
drilldown_searches:
 name:'View the detection results for - "$user_id$" and "$dest$"'
 search:'%original_detection_search% | search user_id = "$user_id$" dest = "$dest$"'
 earliest_offset:'$info_min_time$'
 latest_offset:'$info_max_time$'
 name:'View risk events for the last 7 days for - "$user_id$" and "$dest$"'
 search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user_id$", "$dest$") | 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:'7d'
 latest_offset:'0'
analytic_story:['VMware ESXi AD Integration Authentication Bypass CVE-2024-37085']

asset_type:Endpoint

mitre_attack_id:['T1136.002', 'T1136.001']

product:['Splunk Enterprise', 'Splunk Enterprise Security', 'Splunk Cloud']

category:endpoint

security_domain:endpoint

tags:

tests:
 name:'True Positive Test'
 attack_data:
  data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1136.001/atomic_red_team/windows-powershell-esxadmins.log
  source: XmlWinEventLog:Microsoft-Windows-PowerShell/Operational
  sourcetype: XmlWinEventLog
 test_type:'unit'
manual_test:None