Linux Docker Root Directory Mount

SPLUNK detection rule by Gowthamaraj Rajendran, Splunk, Emil Elsetrønning · Apache-2.0

This detection identifies Docker containers that mount the host's root directory into the container filesystem. Mounting the entire host root directory into a container effectively grants the container visibility and potential write access to all files on the host system. If the container is running as root or with elevated capabilities (e.g., --privileged), the risk is significantly increased.

name: Linux Docker Root Directory Mount
id: aa049566-f76a-43b9-908c-3c27e079fd43
version: 4
creation_date: '2026-03-10'
modification_date: '2026-05-13'
author: Gowthamaraj Rajendran, Splunk, Emil Elsetrønning
status: production
type: TTP
description: |
    This detection identifies Docker containers that mount the host's root directory into the container filesystem.
    Mounting the entire host root directory into a container effectively grants the container visibility and potential write access to all files on the host system.
    If the container is running as root or with elevated capabilities (e.g., --privileged), the risk is significantly increased.
data_source:
    - Sysmon for Linux EventID 1
search: |-
    | tstats `security_content_summariesonly`
      count min(_time) as firstTime
            max(_time) as lastTime
    from datamodel=Endpoint.Processes where
    Processes.process_name=docker*
    Processes.process IN (
      "* -v *",
      "* --volume *"
    )
    Processes.process="* /:/*"
    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)`
    | `linux_docker_root_directory_mount_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: False positives are present based on automated tooling or system administrative usage. Filter as needed.
references:
    - https://docs.docker.com/engine/storage/volumes/
    - https://gtfobins.github.io/gtfobins/docker/
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"
finding:
    title: An instance of $process_name$ spawned by $user$ on endpoint $dest$, tried to mount the root directory via the command $process$
    entity:
        field: user
        type: user
        score: 50
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 50
          message: An instance of $process_name$ spawned by $user$ on endpoint $dest$, tried to mount the root directory via the command $process$
threat_objects:
    - field: process
      type: process
analytic_story:
    - Linux Privilege Escalation
    - Linux Living Off The Land
asset_type: Endpoint
mitre_attack_id:
    - T1611
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/T1548/docker/sysmon_linux.log
          source: Syslog:Linux-Sysmon/Operational
          sourcetype: sysmon:linux
      test_type: unit

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