Powershell Add Name Resolution Policy Table Rule — Sigma Rule

Rule metadata and linked tags

Author: Borna Talebi. Source status: test; severity: high. Source dates: 2021-09-14 / 2022-10-09.

{
  "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: 45b49889677e87a2c5ae803496f5ae982ee3450a502502bab52a587cc76b8eb4

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 Add Name Resolution Policy Table Rule
id: 4368354e-1797-463c-bc39-a309effbe8d7
status: test
description: |
  Detects powershell scripts that adds a Name Resolution Policy Table (NRPT) rule for the specified namespace.
  This will bypass the default DNS server and uses a specified server for answering the query.
references:
    - https://twitter.com/NathanMcNulty/status/1569497348841287681
    - https://learn.microsoft.com/en-us/powershell/module/dnsclient/add-dnsclientnrptrule?view=windowsserver2022-ps
author: Borna Talebi
date: 2021-09-14
modified: 2022-10-09
tags:
    - attack.impact
    - attack.t1565
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains|all:
            - 'Add-DnsClientNrptRule'
            - '-Namesp'
            - '-NameSe'
    condition: selection
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://twitter.com/NathanMcNulty/status/1569497348841287681
• https://learn.microsoft.com/en-us/powershell/module/dnsclient/add-dnsclientnrptrule?view=windowsserver2022-ps