Linux System Network Discovery

name: Linux System Network Discovery
id: 535cb214-8b47-11ec-a2c7-acde48001122
version: 11
creation_date: '2022-02-14'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: |-
    The following analytic identifies potential enumeration of local network configuration on Linux systems.
    It detects this activity by monitoring processes such as "arp," "ifconfig," "ip," "netstat," "firewall-cmd," "ufw," "iptables," "ss," and "route" within a 30-minute window.
    This behavior is significant as it often indicates reconnaissance efforts by adversaries to gather network information for subsequent attacks.
    If confirmed malicious, this activity could enable attackers to map the network, identify vulnerabilities, and plan further exploitation or lateral movement within the environment.
data_source:
    - Sysmon for Linux EventID 1
    - Osquery Results
search: |-
    | tstats `security_content_summariesonly`
      count min(_time) as firstTime
            max(_time) as lastTime
            values(Processes.action) as action
            values(Processes.original_file_name) as original_file_name
            values(Processes.parent_process_exec) as parent_process_exec
            values(Processes.parent_process_guid) as parent_process_guid
            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
            values(Processes.parent_process) as parent_process
            values(Processes.process_exec) as process_exec
            values(Processes.process_guid) as process_guid
            values(Processes.process_hash) as process_hash
            values(Processes.process_id) as process_id
            values(Processes.process_integrity_level) as process_integrity_level
            values(Processes.process_name) as process_name
            values(Processes.process_path) as process_path
            values(Processes.process) as process
            values(Processes.user_id) as user_id
            values(Processes.vendor_product) as vendor_product
            dc(Processes.process_name) as process_name_count
    FROM datamodel=Endpoint.Processes WHERE

    Processes.process_name IN (
        "arp",
        "firewall-cmd",
        "ifconfig",
        "ip",
        "iptables",
        "netstat",
        "route",
        "ss",
        "ufw"
    )

    BY _time span=30m Processes.dest Processes.user

    | where process_name_count>=4

    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `linux_system_network_discovery_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 or network operator can execute this command. Please update the filter macros to remove false positives.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1016/T1016.md
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | 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"
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 20
          message: Network discovery process $process$ executed on $dest$
threat_objects:
    - field: process
      type: command
    - field: process_name
      type: process_name
analytic_story:
    - Data Destruction
    - Network Discovery
    - Industroyer2
    - VoidLink Cloud-Native Linux Malware
asset_type: Endpoint
mitre_attack_id:
    - T1016
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1016/atomic_red_team/linux_net_discovery/sysmon_linux.log
          source: Syslog:Linux-Sysmon/Operational
          sourcetype: sysmon:linux
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1016/atomic_red_team/macos_net_discovery/macos_network_discovery.log
          sourcetype: osquery:results
          source: osquery
      test_type: unit