Windows Delete or Modify System Firewall

name: Windows Delete or Modify System Firewall
id: b188d11a-eba7-419d-b8b6-cc265b4f2c4f
version: 11
date: '2026-03-26'
author: Teoderick Contreras, Splunk
status: production
type: Hunting
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
description: The following analytic identifies 'netsh' processes that delete or modify firewall configurations. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions containing specific keywords. This activity is significant because it can indicate malware, such as NJRAT, attempting to alter firewall settings to evade detection or remove traces. If confirmed malicious, this behavior could allow an attacker to disable security measures, facilitating further compromise and persistence within the network.
search: |-
    | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
      WHERE `process_netsh` Processes.process = "* firewall *" Processes.process = "* del*"
      BY Processes.action Processes.dest Processes.original_file_name
         Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
         Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
         Processes.process Processes.process_exec Processes.process_guid
         Processes.process_hash Processes.process_id Processes.process_integrity_level
         Processes.process_name Processes.process_path Processes.user
         Processes.user_id Processes.vendor_product
    | `drop_dm_object_name("Processes")`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `windows_delete_or_modify_system_firewall_filter`
how_to_implement: The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
known_false_positives: Administrator may modify or delete firewall configuration.
references:
    - https://malpedia.caad.fkie.fraunhofer.de/details/win.njrat
tags:
    analytic_story:
        - NjRAT
        - ShrinkLocker
    asset_type: Endpoint
    mitre_attack_id:
        - T1562.004
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1562.004/njrat_delete_firewall/njrat_delete_firewall.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog