Detection: Linux Docker Root Directory Mount

Updated Date: 2026-03-10 ID: aa049566-f76a-43b9-908c-3c27e079fd43 Author: Gowthamaraj Rajendran, Splunk, Emil Elsetrønning Type: TTP Product: Splunk Enterprise Security

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.

Search

 1
 2| tstats `security_content_summariesonly`
 3  count min(_time) as firstTime
 4        max(_time) as lastTime
 5from datamodel=Endpoint.Processes where
 6Processes.process_name=docker*
 7Processes.process IN (
 8  "* -v *",
 9  "* --volume *"
10)
11Processes.process="* /:/*"
12by Processes.action Processes.dest Processes.original_file_name
13   Processes.parent_process Processes.parent_process_exec
14   Processes.parent_process_guid Processes.parent_process_id
15   Processes.parent_process_name Processes.parent_process_path
16   Processes.process Processes.process_exec Processes.process_guid
17   Processes.process_hash Processes.process_id
18   Processes.process_integrity_level Processes.process_name
19   Processes.process_path Processes.user Processes.user_id Processes.vendor_product
20
21| `drop_dm_object_name(Processes)`
22
23| `security_content_ctime(firstTime)`
24
25| `security_content_ctime(lastTime)`
26
27| `linux_docker_root_directory_mount_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon for Linux EventID 1	Linux	`'sysmon:linux'`	`'Syslog:Linux-Sysmon/Operational'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
linux_docker_root_directory_mount_filter	`search *`

linux_docker_root_directory_mount_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1611	Escape to Host	Privilege Escalation

Exploitation

DE.CM

CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

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.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

An instance of $process_name$ spawned by $user$ on endpoint $dest$, tried to mount the root directory via the command $process$

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	50	process
user	user	50	process

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`Syslog:Linux-Sysmon/Operational`	`sysmon:linux`
Integration	✅ Passing	Dataset	`Syslog:Linux-Sysmon/Operational`	`sysmon:linux`

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 2