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Detection rules › Sigma

Elevated System Shell Spawned

Status
test
Severity
medium
Log source
product windows, category process_creation
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

TacticTechniques
ExecutionT1059 Command and Scripting Interpreter

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

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

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Imageends_with
  • \cmd.exe corpus 130 (sigma 130)
  • \powershell.exe corpus 182 (sigma 182)
  • \powershell_ise.exe corpus 41 (sigma 41)
  • \pwsh.exe corpus 168 (sigma 168)
LogonIdeq
  • 0x3e7 corpus 2 (sigma 2)
OriginalFileNameeq
  • Cmd.Exe corpus 65 (sigma 43, splunk 17, elastic 5)
  • PowerShell.EXE corpus 120 (sigma 84, splunk 30, elastic 6)
  • powershell_ise.EXE corpus 51 (splunk 30, sigma 18, elastic 3)
  • pwsh.dll corpus 112 (sigma 79, splunk 30, elastic 3)
Usermatch
  • AUTHORI corpus 14 (sigma 14)
  • AUTORI corpus 14 (sigma 14)