Sigma Rule Library

New Windows Firewall Rule Added Via New-NetFirewallRule Cmdlet

Detects calls to the "New-NetFirewallRule" cmdlet from PowerShell in order to add a new firewall rule with an "Allow" action.

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Detection logic

selection_name

- Image|endswith:
    - \powershell.exe
    - \pwsh.exe
    - \powershell_ise.exe
- OriginalFileName:
    - PowerShell.EXE
    - pwsh.dll

selection_args

CommandLine|contains|all:
  - "New-NetFirewallRule "
  - " -Action "
  - allow

Condition

all of selection_*

Raw YAML

title: New Windows Firewall Rule Added Via New-NetFirewallRule Cmdlet
id: 51483085-0cba-46a8-837e-4416496d6971
related:
    - id: 8d31dd2e-b582-48ca-826e-dcaa2c1ca264
      type: similar
status: test
description: |
    Detects calls to the "New-NetFirewallRule" cmdlet from PowerShell in order to add a new firewall rule with an "Allow" action.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1562.004/T1562.004.md#atomic-test-24---set-a-firewall-rule-using-new-netfirewallrule
    - https://malware.news/t/the-rhysida-ransomware-activity-analysis-and-ties-to-vice-society/72170
    - https://cybersecuritynews.com/rhysida-ransomware-attacking-windows/
author: frack113
date: 2024-05-03
tags:
    - attack.defense-impairment
    - attack.t1686.003
    - detection.threat-hunting
logsource:
    category: process_creation
    product: windows
detection:
    selection_name:
        - Image|endswith:
              - '\powershell.exe'
              - '\pwsh.exe'
              - '\powershell_ise.exe'
        - OriginalFileName:
              - 'PowerShell.EXE'
              - 'pwsh.dll'
    selection_args:
        CommandLine|contains|all:
            - 'New-NetFirewallRule '
            - ' -Action '
            - 'allow'
    condition: all of selection_*
falsepositives:
    - Administrator script
level: low

False positives

  • Administrator script

References

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