Ensure telnet server services are not in use

MediumLevel 1Automatedlinux

Description

The telnet-server package contains the telnet daemon, which accepts connections from users from other systems via the telnet protocol.

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=$(bash -c 'rpm -q telnet-server' 2>&1); printf '%s\n' "$o" | tr -s ' \t' '  ' | sed 's/^ //;s/ $//' | grep -Fxq -- 'package telnet-server is not installed' || { echo step1: missing 'package telnet-server is not installed'; return 1; }; }; alt1() { command -v grep >/dev/null 2>&1 || { echo "step1: grep not installed"; return 1; }; command -v systemctl >/dev/null 2>&1 || { echo "step1: systemctl not installed"; return 1; }; o=$(bash -c 'systemctl is-enabled telnet.socket 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 telnet.socket 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 telnet.socket and remove the telnet-server package: # systemctl stop telnet.socket # dnf remove telnet-server - OR - - IF - a package is installed and is required for dependencies: Run the following commands to stop and mask telnet.socket: # systemctl stop telnet.socket # systemctl mask telnet.socket

Properties

Operating systems: rocky-9
Tags: cis-convertedlinux
Reference: CIS Rocky Linux 9 Benchmark v3.0.0 - 2.1.15

Check this host

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

shell

tmaegis scan --target linux