Detection: Linux Docker Shell Execution

Description

This detection identifies shell execution activity associated with Docker containers on Linux systems. Specifically, it monitors for interactive or non-interactive shell processes (e.g., /bin/bash, /bin/sh, /bin/zsh) launched via Docker commands such as docker exec, or through container entrypoint overrides. Shell execution inside a container may indicate administrative troubleshooting activity. However, it can also represent post-exploitation behavior, where an attacker gains access to a container and spawns a shell to execute arbitrary commands, establish persistence, or pivot to the host.

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="* exec *"
 8Processes.process IN (
 9  "* /bin/bash *",
10  "* /bin/dash *",
11  "* /bin/sh *",
12  "* /bin/zsh *",
13  "* bash *",
14  "* bash",
15  "* dash *",
16  "* dash",
17  "* sh *",
18  "* sh",
19  "* zsh *",
20  "* zsh"
21)
22by Processes.action Processes.dest Processes.original_file_name
23   Processes.parent_process Processes.parent_process_exec
24   Processes.parent_process_guid Processes.parent_process_id
25   Processes.parent_process_name Processes.parent_process_path
26   Processes.process Processes.process_exec Processes.process_guid
27   Processes.process_hash Processes.process_id
28   Processes.process_integrity_level Processes.process_name
29   Processes.process_path Processes.user Processes.user_id Processes.vendor_product
30
31| `drop_dm_object_name(Processes)`
32
33| `security_content_ctime(firstTime)`
34
35| `security_content_ctime(lastTime)`
36
37| `linux_docker_shell_execution_filter`

Data Source

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

Macros Used

Annotations

Default Configuration

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

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

• Linux Living Off The Land

• Linux Privilege Escalation

Risk Based Analytics (RBA)

Risk Message:

$user$ on endpoint $dest$ spawned a shell in a docker container via the commandline $process$

References

• https://docs.docker.com/reference/cli/docker/container/exec/

• https://gtfobins.github.io/gtfobins/docker/

Detection Testing

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