Ensure that host devices are not directly exposed to containers

MediumLevel 1Automateddocker

Description

Host devices passed with --device give the container direct access to hardware, bypassing isolation. Flags containers with any HostConfig.Devices entry. The audit inspects every running container (docker ps -q) and prints the offending names; a host with no running containers is compliant.

How it is checked

Audit method: Shell command

shell

ids=$(docker ps -q) || exit 1; [ -z "$ids" ] && { echo compliant; exit 0; }; out=$(docker inspect --format '{{.Name}} {{len .HostConfig.Devices}}' $ids) || exit 1; bad=$(printf '%s\n' "$out" | awk '$2+0>0{print $1}'); [ -z "$bad" ] && echo compliant || printf '%s\n' "$bad"

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Redeploy without --device unless strictly required; if required, grant the minimum permissions (e.g. --device=/dev/xyz:/dev/xyz:r).

Properties

Operating systems: Any
Tags: dockerruntime
Reference: CIS Docker Benchmark v1.9.0 - 5.18 Ensure that host devices are not directly exposed to containers

Check this host

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

shell

tmaegis scan --target docker