Suspicious Group And Account Recon Behavior Via Net.EXE (via process_creation)

title: Suspicious Group And Account Recon Behavior Via Net.EXE (via process_creation)
id: 0742a2d6-bfe2-555f-94e8-bcb6a6fe8fa0
status: stable
description: This rule detects anomalous reconnaissance command line behavior on Windows systems using Net.EXE Check if the user that executed the commands is anomalous (e.g. service accounts, LOCAL_SYSTEM)
references:
    - https://attack.mitre.org/techniques/T1087/002/
    - https://attack.mitre.org/techniques/T1087/001/
    - https://redcanary.com/blog/how-one-hospital-thwarted-a-ryuk-ransomware-outbreak/
    - https://thedfirreport.com/2020/10/18/ryuk-in-5-hours/
    - https://research.nccgroup.com/2022/08/19/back-in-black-unlocking-a-lockbit-3-0-ransomware-attack/
author: Huntrule Team
date: 2026-07-03
tags:
    - attack.discovery
    - attack.t1087.001
    - attack.t1087.002
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith:
              - '\net.exe'
              - '\net1.exe'
        - OriginalFileName:
              - 'net.exe'
              - 'net1.exe'
    selection_group_root:
        CommandLine|contains:
            - ' group '
            - ' localgroup '
    selection_group_flags:
        CommandLine|contains:
            - 'domain admins'
            - ' administrator'
            - ' administrateur'
            - 'enterprise admins'
            - 'Exchange Trusted Subsystem'
            - 'Remote Desktop Users'
            - 'Utilisateurs du Bureau à distance'
            - 'Usuarios de escritorio remoto'
            - ' /do'
    filter_group_add:
        CommandLine|contains: ' /add'
    selection_accounts_root:
        CommandLine|contains: ' accounts '
    selection_accounts_flags:
        CommandLine|contains: ' /do'
    condition: selection_img and ((all of selection_group_* and not filter_group_add) or all of selection_accounts_*)
falsepositives:
    - Unknown
level: medium