Conhost Spawned By Uncommon Parent Process — Sigma Rule

Rule metadata and linked tags

Author: Tim Rauch, Elastic (idea). Source status: test; severity: medium. Source dates: 2022-09-28 / 2025-03-06.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 3a4cd3f28002b84c60e91450e161da6353103c49b6a174f1d85b77244144b7a2

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Conhost Spawned By Uncommon Parent Process
id: cbb9e3d1-2386-4e59-912e-62f1484f7a89
status: test
description: Detects when the Console Window Host (conhost.exe) process is spawned by an uncommon parent process, which could be indicative of potential code injection activity.
references:
    - https://www.elastic.co/guide/en/security/current/conhost-spawned-by-suspicious-parent-process.html
author: Tim Rauch, Elastic (idea)
date: 2022-09-28
modified: 2025-03-06
tags:
    - attack.execution
    - attack.t1059
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\conhost.exe'
        ParentImage|endswith:
            - '\explorer.exe'
            # - '\csrss.exe'  # Legitimate parent as seen in EchoTrail https://www.echotrail.io/insights/search/csrss.exe
            # - '\ctfmon.exe'  # Seen several times in a testing environment
            # - '\dllhost.exe'  # FP on clean system from grandparent 'svchost.exe -k DcomLaunch -p'
            - '\lsass.exe'
            - '\regsvr32.exe'
            - '\rundll32.exe'
            - '\services.exe'
            - '\smss.exe'
            - '\spoolsv.exe'
            - '\svchost.exe'
            - '\userinit.exe'
            # - '\wermgr.exe'  # Legitimate parent as seen in EchoTrail https://www.echotrail.io/insights/search/wermgr.exe
            - '\wininit.exe'
            - '\winlogon.exe'
    filter_main_svchost:
        ParentCommandLine|contains:
            - '-k apphost -s AppHostSvc'
            - '-k imgsvc'
            - '-k localService -p -s RemoteRegistry'
            - '-k LocalSystemNetworkRestricted -p -s NgcSvc'
            - '-k NetSvcs -p -s NcaSvc'
            - '-k netsvcs -p -s NetSetupSvc'
            - '-k netsvcs -p -s wlidsvc'
            - '-k NetworkService -p -s DoSvc'
            - '-k wsappx -p -s AppXSvc'
            - '-k wsappx -p -s ClipSVC'
            - '-k wusvcs -p -s WaaSMedicSvc'
    filter_optional_dropbox:
        ParentCommandLine|contains:
            - 'C:\Program Files (x86)\Dropbox\Client\'
            - 'C:\Program Files\Dropbox\Client\'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.elastic.co/guide/en/security/current/conhost-spawned-by-suspicious-parent-process.html