Ensure Userland Proxy is Disabled

LowLevel 1Automateddocker

Description

The userland proxy (docker-proxy) adds attack surface; hairpin NAT through iptables is preferred. Compliant when userland-proxy is set to false. The audit reads the running dockerd command line (ps) together with /etc/docker/daemon.json.

How it is checked

Audit method: Shell command

shell

args=$(ps -eo args 2>/dev/null) || exit 1; s=$(printf '%s\n' "$args" | grep '[d]ockerd'; cat /etc/docker/daemon.json 2>/dev/null); printf '%s\n' "$s" | grep -Eq -e '--userland-proxy[= ]+false|"userland-proxy"[[:space:]]*:[[:space:]]*false' && echo compliant || echo missing

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Set "userland-proxy": false in /etc/docker/daemon.json and restart the Docker daemon.

Properties

Operating systems: Any
Tags: dockerdaemonnetwork
Reference: CIS Docker Benchmark v1.9.0 - 2.17 Ensure Userland Proxy is Disabled

Check this host

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

shell

tmaegis scan --target docker