MacOS Network Share Discovery

name: MacOS Network Share Discovery
id: a5f5fe52-8e50-4fb0-ad1b-780be6c0d857
version: 2
date: '2026-04-15'
author: Raven Tait, Splunk
status: production
type: Anomaly
description: |-
    Identifies execution of network share enumeration commands (smbutil, showmount) that can be leveraged by adversaries to discover accessible SMB and NFS resources, supporting internal reconnaissance and potential lateral movement.
data_source:
    - Osquery Results
search: |-
    | tstats `security_content_summariesonly`
      count min(_time) as firstTime
            max(_time) as lastTime

    from datamodel=Endpoint.Processes where

    Processes.process IN ("*showmount *", "*smbutil *")

    by Processes.dest Processes.original_file_name Processes.parent_process_id
       Processes.process Processes.process_exec Processes.process_guid
       Processes.process_hash Processes.process_id
       Processes.process_current_directory 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)`
    | `macos_network_share_discovery_filter`
how_to_implement: |-
    This detection uses osquery and endpoint security on MacOS. Follow the link in references, which describes how to setup process auditing in MacOS with endpoint security and osquery.
    Also the [TA-OSquery](https://splunkbase.splunk.com/app/8574) must be deployed across your indexers and universal forwarders in order to have the osquery data populate the data models.
known_false_positives: |-
    Administrators may utilize these tools occasionaly for troubleshooting.
references:
    - https://osquery.readthedocs.io/en/stable/deployment/process-auditing/
    - https://leopard-adc.pepas.com/documentation/Darwin/Reference/ManPages/man8/showmount.8.html
    - https://www.unix.com/man_page/osx/1/smbutil/
drilldown_searches:
    - name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$user$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
rba:
    message: Network share information enumerated on $dest$ by $user$ via $process$
    risk_objects:
        - field: user
          type: user
          score: 20
        - field: dest
          type: system
          score: 20
    threat_objects:
        - field: process
          type: process
tags:
    analytic_story:
        - MacOS Post-Exploitation
    asset_type: Endpoint
    mitre_attack_id:
        - T1135
    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/T1135/osquery_share_discovery/osquery.log
          source: osquery
          sourcetype: osquery:results