Ensure that all Docker swarm overlay networks are encrypted

MediumLevel 1Automateddocker

Description

Overlay network traffic between swarm nodes is unencrypted by default. On an active swarm node every overlay network must have the encrypted option; compliant when swarm mode is inactive.

How it is checked

Audit method: Shell command

shell

st=$(docker info --format '{{.Swarm.LocalNodeState}}') || exit 1; [ "$st" = active ] || { echo compliant; exit 0; }; ns=$(docker network ls --filter driver=overlay --quiet) || exit 1; [ -z "$ns" ] && { echo compliant; exit 0; }; out=$(docker network inspect --format '{{.Name}} {{index .Options "encrypted"}}' $ns) || exit 1; bad=$(printf '%s\n' "$out" | awk 'NF<2 {print $1}'); [ -z "$bad" ] && echo compliant || printf 'unencrypted overlay: %s\n' $bad

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Create overlay networks with --opt encrypted (docker network create -d overlay --opt encrypted <name>) and move services onto them.

Properties

Operating systems: Any
Tags: dockerswarmnetwork
Reference: CIS Docker Benchmark v1.9.0 - 7.3 Ensure that all Docker swarm overlay networks are encrypted

Check this host

Run this on a machine you are allowed to audit. The scan is read-only.

shell

tmaegis scan --target docker