Ensure avahi daemon services are not in use

MediumLevel 1Automatedlinux

Description

Avahi is a free zeroconf implementation, including a system for multicast DNS/DNS-SD service discovery. Avahi allows programs to publish and discover services and hosts running on a local network with no specific configuration. For example, a user can plug a computer into a network and Avahi automatically finds printers to print to, files to look at and people to talk to, as well as network services running on the machine.

How it is checked

Audit method: Shell command

shell

alt0() { command -v rpm >/dev/null 2>&1 || { echo "step1: rpm not installed"; return 1; }; o=$(bash -c 'rpm -q avahi' 2>&1); printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'package avahi is not installed' || { echo step1: missing 'package avahi is not installed'; return 1; }; }; alt1() { command -v grep >/dev/null 2>&1 || { echo "step1: grep not installed"; return 1; }; command -v systemctl >/dev/null 2>&1 || { echo "step1: systemctl not installed"; return 1; }; o=$(bash -c 'systemctl is-enabled avahi-daemon.socket avahi-daemon.service 2>/dev/null | grep '"'"'enabled'"'"'' 2>/dev/null); [ -z "$o" ] || { echo "step1: $o" | head -c 300; return 1; }; command -v grep >/dev/null 2>&1 || { echo "step2: grep not installed"; return 1; }; command -v systemctl >/dev/null 2>&1 || { echo "step2: systemctl not installed"; return 1; }; o=$(bash -c 'systemctl is-active avahi-daemon.socket avahi-daemon.service 2>/dev/null | grep '"'"'^active'"'"'' 2>/dev/null); [ -z "$o" ] || { echo "step2: $o" | head -c 300; return 1; }; }; if alt0 || alt1; then echo compliant; fi

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Run the following commands to stop avahi-daemon.socket and avahi- daemon.service, and remove the avahi package: # systemctl stop avahi-daemon.socket avahi-daemon.service # dnf remove avahi - OR - - IF - the avahi package is required as a dependency: Run the following commands to stop and mask the avahi-daemon.socket and avahi- daemon.service: # systemctl stop avahi-daemon.socket avahi-daemon.service # systemctl mask avahi-daemon.socket avahi-daemon.service

Properties

Operating systems: alinux-3
Tags: cis-convertedlinux
Reference: CIS Alibaba Cloud Linux 3 Benchmark v2.0.0 - 2.1.2

Check this host

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

shell

tmaegis scan --target linux