MacOS List Firewall Rules

name: MacOS List Firewall Rules
id: f8db6e0b-55bb-40ca-bc85-2b3700adb0f8
version: 2
creation_date: '2026-04-15'
modification_date: '2026-05-13'
author: Jamie Windley, Splunk
status: production
type: Anomaly
description: |
    This analytic detects attempts to enumerate or verify the configuration of the macOS application firewall.
    Specifically, it monitors executions of `defaults read /Library/Preferences/com.apple.alf` and `/usr/libexec/ApplicationFirewall/socketfilterfw --getglobalstate`.
    These commands provide insight into firewall status, allowed applications, and explicit authorization rules.
    While they are legitimate administrative operations, adversaries may leverage them to identify potential attack surfaces, determine whether the firewall is active, or enumerate allowed network flows.
    Monitoring for these commands, particularly when executed by non-administrative users or at unusual times, can provide early indication of reconnaissance activity on macOS endpoints
data_source:
    - Osquery Results
search: |
    | tstats `security_content_summariesonly`
      count
      values(Processes.parent_process) AS parent_process
      values(Processes.parent_process_exec) AS parent_process_exec
      values(Processes.parent_process_id) AS parent_process_id
      values(Processes.parent_process_name) AS parent_process_name
      values(Processes.parent_process_path) AS parent_process_path
      min(_time) as firstTime
      max(_time) as lastTime
    
    from datamodel=Endpoint.Processes where
    (
    Processes.process_name = "defaults"
    Processes.process = "* read *",
    Processes.process = "*/Library/Preferences/com.apple.alf*"
    )
    OR
    (
      Processes.process_name = "socketfilterfw"
      Processes.process = "*--getglobalstate*"
    )
    
    by Processes.action Processes.dest Processes.process Processes.process_hash
       Processes.process_id Processes.process_name Processes.process_path
       Processes.user Processes.vendor_product
    
    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `macos_list_firewall_rules_filter`
how_to_implement: |
    Collection of process execution events from macOS endpoints is required. This can be achieved using osquery's `es_process_events` table, EndpointSecurity framework integrations, or an EDR platform capable of recording process command lines. Ensure that captured events include at least the process path, full command line, user context, and timestamp.
known_false_positives: |
    These commands are frequently executed by system administrators or IT personnel during routine configuration checks, troubleshooting, or automated maintenance scripts. Security tools or monitoring agents may also query firewall status for inventory or compliance purposes. To reduce false positives, consider excluding events from known administrative accounts, trusted management systems, or scheduled maintenance jobs.
references:
    - https://www.manpagez.com/man/8/socketfilterfw/
    - https://ss64.com/mac/defaults.html
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 20
          message: MacOS firewall rules listed via $process_name$ by $user$ on $dest$ using the command line $process$
        - field: user
          type: user
          score: 20
          message: MacOS firewall rules listed via $process_name$ by $user$ on $dest$ using the command line $process$
threat_objects:
    - field: parent_process_name
      type: parent_process_name
    - field: process
      type: command
    - field: process_name
      type: process_name
analytic_story:
    - Network Discovery
asset_type: Endpoint
mitre_attack_id:
    - T1016
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint