cis-docker-v160-2-8

name	cis-docker-v160-2.8
description	Ensure the default ulimit is configured appropriately
category	cis-docker
version	1.6.0
author	cyberstrike-official
tags	["cis","docker","daemon","ulimit","resource-limits","dos-prevention"]
cis_id	2.8
cis_benchmark	CIS Docker Benchmark v1.6.0
tech_stack	["docker"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

Ensure the default ulimit is configured appropriately

Profile Applicability: Level 1 - Docker - Linux

Assessment Status: Manual

Description

Set the default ulimit options as appropriate in your environment.

Rationale

ulimit provides control over the resources available to the shell and to processes which it starts. Setting system resource limits judiciously can save you from disasters such as a fork bomb. On occasion, even friendly, legitimate processes can overuse system resources and can make the system unusable.

Setting the default ulimit for the Docker daemon enforces the ulimit for all container instances. In this case you would not need to setup ulimit for each container instance. However, the default ulimit can be overridden during container runtime, if needed. Therefore, in order to have proper control over system resources, define a default ulimit as is needed in your environment.

Impact

If ulimits are set incorrectly this could cause issues with system resources, possibly causing a denial of service condition.

Audit Procedure

To confirm this setting you should review the dockerd start-up options and any settings in /etc/docker/daemon.json. To review the dockerd startup options, use:

ps -ef | grep dockerd

Ensure that the --default-ulimit parameter is set as appropriate. The contents of /etc/docker/daemon.json should also be reviewed for this setting.

Remediation

Run Docker in daemon mode and pass --default-ulimit as argument with respective ulimits as appropriate in your environment and in line with your security policy. For Example,

dockerd --default-ulimit nproc=1024:2048 --default-ulimit nofile=100:200

Default Value

By default, no ulimit is set.

References

1. https://docs.docker.com/engine/reference/commandline/dockerd/#default-ulimit-settings

CIS Controls

Controls Version	Control	IG 1	IG 2	IG 3
v8	16.7 Use Standard Hardening Configuration Templates for Application Infrastructure Use standard, industry-recommended hardening configuration templates for application infrastructure components. This includes underlying servers, databases, and web servers, and applies to cloud containers, Platform as a Service (PaaS) components, and SaaS components. Do not allow in-house developed software to weaken configuration hardening.