Powershell Add Name Resolution Policy Table Rule

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.

Sigma rule (View on GitHub)

 1title: Powershell Add Name Resolution Policy Table Rule
 2id: 4368354e-1797-463c-bc39-a309effbe8d7
 3status: test
 4description: |
 5  Detects powershell scripts that adds a Name Resolution Policy Table (NRPT) rule for the specified namespace.
 6  This will bypass the default DNS server and uses a specified server for answering the query.  
 7references:
 8    - https://twitter.com/NathanMcNulty/status/1569497348841287681
 9    - https://learn.microsoft.com/en-us/powershell/module/dnsclient/add-dnsclientnrptrule?view=windowsserver2022-ps
10author: Borna Talebi
11date: 2021/09/14
12modified: 2022/10/09
13tags:
14    - attack.impact
15    - attack.t1565
16logsource:
17    product: windows
18    category: ps_script
19    definition: 'Requirements: Script Block Logging must be enabled'
20detection:
21    selection:
22        ScriptBlockText|contains|all:
23            - 'Add-DnsClientNrptRule'
24            - '-Namesp'
25            - '-NameSe'
26    condition: selection
27falsepositives:
28    - Unknown
29level: high

References

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