PowerShell Remote Session Creation — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: medium. Source dates: 2022-01-06 / 2023-01-02.

{
  "product": "windows",
  "category": "ps_script",
  "definition": "Requirements: Script Block Logging must be enabled"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 0452efd9b696b2051b5de02a19b7b06795ef905a993b2474bd48a683557780d3

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: PowerShell Remote Session Creation
id: a0edd39f-a0c6-4c17-8141-261f958e8d8f
status: test
description: |
    Adversaries may abuse PowerShell commands and scripts for execution.
    PowerShell is a powerful interactive command-line interface and scripting environment included in the Windows operating system
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1059.001/T1059.001.md#atomic-test-10---powershell-invoke-downloadcradle
    - https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/new-pssession?view=powershell-7.4
author: frack113
date: 2022-01-06
modified: 2023-01-02
tags:
    - attack.execution
    - attack.t1059.001
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains|all:
            - 'New-PSSession'
            - '-ComputerName '
    condition: selection
falsepositives:
    - Legitimate administrative script
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate administrative script

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1059.001/T1059.001.md#atomic-test-10---powershell-invoke-downloadcradle
• https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/new-pssession?view=powershell-7.4