WmiPrvSE Spawned A Process

Hunt Hypothesis

Detects WmiPrvSE spawning a process

Detection Rule

Sigma (Original)

title: WmiPrvSE Spawned A Process
id: d21374ff-f574-44a7-9998-4a8c8bf33d7d
related:
    - id: 8a582fe2-0882-4b89-a82a-da6b2dc32937
      type: similar
    - id: 692f0bec-83ba-4d04-af7e-e884a96059b6
      type: similar
status: stable
description: Detects WmiPrvSE spawning a process
references:
    - https://threathunterplaybook.com/hunts/windows/190815-RemoteServiceInstallation/notebook.html
author: Roberto Rodriguez @Cyb3rWard0g
date: 2019-08-15
modified: 2023-03-23
tags:
    - attack.execution
    - attack.t1047
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\WmiPrvSe.exe'
    filter_logonid:
        LogonId:
            - '0x3e7'  # LUID 999 for SYSTEM
            - 'null'   # too many false positives
    filter_system_user:
        User|contains: # covers many language settings
            - 'AUTHORI'
            - 'AUTORI'
    filter_wmiprvse:
        Image|endswith: '\WmiPrvSE.exe'
    filter_werfault:
        Image|endswith: '\WerFault.exe'
    filter_null:  # some backends need the null value in a separate expression
        LogonId: null
    condition: selection and not 1 of filter_*
falsepositives:
    - False positives are expected (e.g. in environments where WinRM is used legitimately)
level: medium

KQL (Azure Sentinel)

imProcessCreate
| where (ParentProcessName endswith "\\WmiPrvSe.exe" or ActingProcessName endswith "\\WmiPrvSe.exe") and (not(((TargetUserSessionId in~ ("0x3e7", "null")) or (TargetUsername contains "AUTHORI" or TargetUsername contains "AUTORI") or TargetProcessName endswith "\\WmiPrvSE.exe" or TargetProcessName endswith "\\WerFault.exe" or isnull(TargetUserSessionId))))

Required Data Sources

False Positive Guidance

• False positives are expected (e.g. in environments where WinRM is used legitimately)

MITRE ATT&CK Context

• Tactic: Execution
• Technique: T1047 — T1047

References

• https://threathunterplaybook.com/hunts/windows/190815-RemoteServiceInstallation/notebook.html
• SigmaHQ Rule