cis-docker-5.30

DevOps & Security

Ensure that Docker's default bridge docker0 is not used

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5.30 Ensure that Docker's default bridge "docker0" is not used (Manual)

Profile Applicability

Level 2 - Docker - Linux

Description

You should not use Docker's default bridge docker0. Instead you should use Docker's user-defined networks for container networking.

Rationale

Docker connects virtual interfaces created in bridge mode to a common bridge called docker0. This default networking model is vulnerable to ARP spoofing and MAC flooding attacks as there is no filtering applied to it.

Impact

User-defined networks need to be configured and managed in line with organizational security policy.

Audit Procedure

You should run the command below, and verify that containers are on a user-defined network and not the default docker0 bridge.

docker network ls --quiet | xargs docker network inspect --format '{{ .Name }}: {{ .Options }}'

Remediation

You should follow the Docker documentation and set up a user-defined network. All the containers should be run in this network.

Default Value

By default, Docker runs containers within the default docker0 bridge.

References

https://docs.docker.com/network/bridge/

CIS Controls

Controls Version	Control	IG 1	IG 2	IG 3
v8	4.8 Uninstall or Disable Unnecessary Services on Enterprise Assets and SoftwareUninstall or disable unnecessary services on enterprise assets and software, such as an unused file sharing service, web application module, or service function.		●	●
v6	9 Limitation and Control of Network Ports, Protocols, and ServicesLimitation and Control of Network Ports, Protocols, and Services