Potentially Suspicious Child Processes Spawned by ConHost — Sigma Rule

Rule metadata and linked tags

Author: Swachchhanda Shrawan Poudel (Nextron Systems). Source status: experimental; severity: high. Source dates: 2025-02-05 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: cbd77556fd15c351d3b9ea7b124b798b4928e61527cb9cba4ece9729141a6be3

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: Potentially Suspicious Child Processes Spawned by ConHost
id: dfa03a09-8b92-4d83-8e74-f72839b1c407
related:
    - id: 7dc2dedd-7603-461a-bc13-15803d132355
      type: similar
status: experimental
description: Detects suspicious child processes related to Windows Shell utilities spawned by `conhost.exe`, which could indicate malicious activity using trusted system components.
references:
    - https://tria.ge/241015-l98snsyeje/behavioral2
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-02-05
tags:
    - attack.stealth
    - attack.t1202
    - attack.t1218
logsource:
    category: process_creation
    product: windows
detection:
    selection_parent:
        ParentImage|endswith: '\conhost.exe'
    selection_child:
        - Image|endswith:
              - '\cmd.exe'             # Windows Command Prompt
              - '\cscript.exe'         # Windows Script Host (used for scripting exploits)
              - '\mshta.exe'           # MSHTA (HTML Application Host, often abused)
              - '\powershell_ise.exe'  # PowerShell ISE
              - '\powershell.exe'      # Windows PowerShell
              - '\pwsh.exe'            # PowerShell Core
              - '\regsvr32.exe'        # Windows Registry Server (commonly used for exploits)
              - '\wscript.exe'         # Windows Script Host (for executing scripts)
        - OriginalFileName:
              - 'cmd.exe'
              - 'cscript.exe'
              - 'mshta.exe'
              - 'powershell_ise.exe'
              - 'powershell.exe'
              - 'pwsh.dll'
              - 'regsvr32.exe'
              - 'wscript.exe'
    condition: all of selection_*
falsepositives:
    - Legitimate administrative tasks using `conhost.exe` to spawn child processes such as `cmd.exe`, `powershell.exe`, or `regsvr32.exe`.
level: high

Original YAML and metadata in JSON

False positives

• Legitimate administrative tasks using `conhost.exe` to spawn child processes such as `cmd.exe`, `powershell.exe`, or `regsvr32.exe`.

Source references

• https://tria.ge/241015-l98snsyeje/behavioral2