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V-235828

CAT II (Medium)

PIDs cgroup limits must be used in Docker Enterprise.

Rule ID

SV-235828r961155_rule

STIG

Docker Enterprise 2.x Linux/UNIX Security Technical Implementation Guide

Version

V2R2

CCIs

CCI-001095

Discussion

Use --pids-limit flag at container runtime. Attackers could launch a fork bomb with a single command inside the container. This fork bomb can crash the entire system and requires a restart of the host to make the system functional again. PIDs cgroup --pids-limit will prevent this kind of attacks by restricting the number of forks that can happen inside a container at a given time. The Default value for --pids-limit is 0 which means there is no restriction on the number of forks. Also, note that PIDs cgroup limit works only for the kernel versions 4.3+.

Check Content

This check only applies to the use of Docker Engine - Enterprise on a Linux host operating system.

Ensure PIDs cgroup limit is used.

via CLI:

Linux: As a Docker EE Admin, execute the following command using a Universal Control Plane (UCP) client bundle:

docker ps --quiet --all | xargs docker inspect --format '{{ .Id }}: PidsLimit={{ .HostConfig.PidsLimit }}'

Ensure that PidsLimit is not set to 0 or -1. A PidsLimit of 0 or -1 means that any number of processes can be forked inside the container concurrently. If the PidsLimit is set to either 0 or -1 then this is a finding.

Fix Text

This fix only applies to the use of Docker Engine - Enterprise on a Linux host operating system.

Use --pids-limit flag while launching the container with an appropriate value.

Example:
docker run -it --pids-limit 100 <Image_ID>
In the above example, the number of processes allowed to run at any given time is set to 100. After a limit of 100 concurrently running processes is reached, docker would restrict any new process creation.