Elevated System Shell Spawned

Status: test
Severity: medium
Log source: category process_creation, product windows
Author: Nasreddine Bencherchali (Nextron Systems), frack113
Source: github.com/SigmaHQ/sigma

Detects when a shell program such as the Windows command prompt or PowerShell is launched with system privileges. Use this rule to hunt for potential suspicious processes.

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059` Command and Scripting Interpreter

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation

Rule body

title: Elevated System Shell Spawned
id: 61065c72-5d7d-44ef-bf41-6a36684b545f
related:
    - id: 178e615d-e666-498b-9630-9ed363038101
      type: similar
status: test
description: |
    Detects when a shell program such as the Windows command prompt or PowerShell is launched with system privileges. Use this rule to hunt for potential suspicious processes.
references:
    - https://github.com/Wh04m1001/SysmonEoP
author: Nasreddine Bencherchali (Nextron Systems), frack113
date: 2023-11-23
modified: 2025-03-06
tags:
    - attack.privilege-escalation
    - attack.execution
    - attack.t1059
    - detection.threat-hunting
logsource:
    product: windows
    category: process_creation
detection:
    selection_shell:
        - Image|endswith:
              - '\powershell.exe'
              - '\powershell_ise.exe'
              - '\pwsh.exe'
              - '\cmd.exe'
        - OriginalFileName:
              - 'PowerShell.EXE'
              - 'powershell_ise.EXE'
              - 'pwsh.dll'
              - 'Cmd.Exe'
    selection_user:
        User|contains: # covers many language settings
            - 'AUTHORI'
            - 'AUTORI'
        LogonId: '0x3e7'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: `condition`

all of selection_*

Stage 1: `selection_shell`

selection_shell:
    - Image|endswith:
          - '\powershell.exe'
          - '\powershell_ise.exe'
          - '\pwsh.exe'
          - '\cmd.exe'
    - OriginalFileName:
          - 'PowerShell.EXE'
          - 'powershell_ise.EXE'
          - 'pwsh.dll'
          - 'Cmd.Exe'

Stage 2: `selection_user`

selection_user:
    User|contains:
        - 'AUTHORI'
        - 'AUTORI'
    LogonId: '0x3e7'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`Image`	ends_with	`\cmd.exe` corpus 130 (sigma 130) `\powershell.exe` corpus 179 (sigma 178, kusto 1) `\powershell_ise.exe` corpus 41 (sigma 41) `\pwsh.exe` corpus 165 (sigma 164, kusto 1)	`field:"Image" kind:ends_with`
`LogonId`	eq	`0x3e7` corpus 2 (sigma 2)	`field:"LogonId" kind:eq value:"0x3e7"`
`OriginalFileName`	eq	`Cmd.Exe` corpus 81 (sigma 43, elastic 21, splunk 17) `PowerShell.EXE` corpus 138 (sigma 84, splunk 30, elastic 24) `powershell_ise.EXE` corpus 51 (splunk 30, sigma 18, elastic 3) `pwsh.dll` corpus 112 (sigma 79, splunk 30, elastic 3)	`field:"OriginalFileName" kind:eq`
`User`	match	`AUTHORI` corpus 14 (sigma 14) `AUTORI` corpus 14 (sigma 14)	`field:"user" kind:match`