Detection rules › Sigma

Potential Exploitation of CVE-2024-37085 - Suspicious Creation Of ESX Admins Group

Status
test
Severity
high
Log source
product windows, category process_creation
Author
frack113
Source
github.com/SigmaHQ/sigma

Detects execution of the "net.exe" command in order to add a group named "ESX Admins". This could indicates a potential exploitation attempt of CVE-2024-37085, which allows an attacker to elevate their privileges to full administrative access on an domain-joined ESXi hypervisor. VMware ESXi hypervisors joined to an Active Directory domain consider any member of a domain group named "ESX Admins" to have full administrative access by default.

MITRE ATT&CK coverage

TacticTechniques
ExecutionNo specific technique

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: Potential Exploitation of CVE-2024-37085 - Suspicious Creation Of ESX Admins Group
id: c408acfe-2870-41df-8d2f-9f4daa4555ed
status: test
description: |
    Detects execution of the "net.exe" command in order to add a group named "ESX Admins".
    This could indicates a potential exploitation attempt of CVE-2024-37085, which allows an attacker to elevate their privileges to full administrative access on an domain-joined ESXi hypervisor.
    VMware ESXi hypervisors joined to an Active Directory domain consider any member of a domain group named "ESX Admins" to have full administrative access by default.
references:
    - https://www.microsoft.com/en-us/security/blog/2024/07/29/ransomware-operators-exploit-esxi-hypervisor-vulnerability-for-mass-encryption/
author: frack113
date: 2024-07-29
tags:
    - attack.execution
    - cve.2024-37085
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection_net_img:
        - Image|endswith:
              - '\net.exe'
              - '\net1.exe'
        - OriginalFileName:
              - 'net.exe'
              - 'net1.exe'
    selection_net_cmd:
        CommandLine|contains|all:
            - '/add'
            - '/domain'
            - 'ESX Admins'
            - 'group'
    selection_powershell_img:
        - Image|endswith:
              - '\PowerShell.exe'
              - '\pwsh.exe'
        - OriginalFileName:
              - 'PowerShell.exe'
              - 'pwsh.dll'
    selection_powershell_cli:
        CommandLine|contains|all:
            - 'New-ADGroup'
            - 'ESX Admins'
    condition: all of selection_net_* or all of selection_powershell_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

all of selection_net_* or all of selection_powershell_*

Stage 1: selection_net_img

selection_net_img:
    - Image|endswith:
          - '\net.exe'
          - '\net1.exe'
    - OriginalFileName:
          - 'net.exe'
          - 'net1.exe'

Stage 2: selection_net_cmd

selection_net_cmd:
    CommandLine|contains|all:
        - '/add'
        - '/domain'
        - 'ESX Admins'
        - 'group'

Stage 3: selection_powershell_img

selection_powershell_img:
    - Image|endswith:
          - '\PowerShell.exe'
          - '\pwsh.exe'
    - OriginalFileName:
          - 'PowerShell.exe'
          - 'pwsh.dll'

Stage 4: selection_powershell_cli

selection_powershell_cli:
    CommandLine|contains|all:
        - 'New-ADGroup'
        - 'ESX Admins'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
CommandLinematch
  • /add corpus 9 (sigma 5, splunk 2, kusto 2)
  • /domain
  • ESX Admins corpus 2 (sigma 1, splunk 1)
  • New-ADGroup
  • group corpus 7 (splunk 4, sigma 3)
Imageends_with
  • \PowerShell.exe corpus 182 (sigma 182)
  • \net.exe corpus 49 (sigma 49)
  • \net1.exe corpus 47 (sigma 47)
  • \pwsh.exe corpus 168 (sigma 168)
OriginalFileNameeq
  • PowerShell.exe corpus 120 (sigma 84, splunk 30, elastic 6)
  • net.exe corpus 28 (sigma 19, elastic 7, splunk 2)
  • net1.exe corpus 44 (sigma 19, splunk 19, elastic 6)
  • pwsh.dll corpus 112 (sigma 79, splunk 30, elastic 3)