The macOS system must not use telnet.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-81643	AOSX-13-000605	SV-96357r1_rule		High

Description
The "telnet" service must be disabled as it sends all data in a clear-text form that can be easily intercepted and read. The data needs to be protected at all times during transmission, and encryption is the standard method for protecting data in transit. If the data is not encrypted during transmission, it can be plainly read (i.e., clear text) and easily compromised. Disabling telnet is one way to mitigate this risk. Administrators should be instructed to use an alternate service for remote access sessions, non-local maintenance sessions, and diagnostic communications that uses encryption, such as SSH. Satisfies: SRG-OS-000074-GPOS-00042, SRG-OS-000125-GPOS-00065, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174

Description

The "telnet" service must be disabled as it sends all data in a clear-text form that can be easily intercepted and read. The data needs to be protected at all times during transmission, and encryption is the standard method for protecting data in transit. If the data is not encrypted during transmission, it can be plainly read (i.e., clear text) and easily compromised. Disabling telnet is one way to mitigate this risk. Administrators should be instructed to use an alternate service for remote access sessions, non-local maintenance sessions, and diagnostic communications that uses encryption, such as SSH. Satisfies: SRG-OS-000074-GPOS-00042, SRG-OS-000125-GPOS-00065, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174

STIG	Date
Apple OS X 10.13 Security Technical Implementation Guide	2019-03-08

Details

Check Text ( C-81419r1_chk )
To check if the "telnet" service is disabled, use the following command: /usr/bin/sudo /bin/launchctl print-disabled system \| /usr/bin/grep com.apple.telnetd If the results do not show the following, this is a finding: "com.apple.telnetd" => true

Fix Text (F-88491r1_fix)
To disable the "telnet" service, run the following command: /usr/bin/sudo /bin/launchctl disable system/com.apple.telnetd The system may need to be restarted for the update to take effect.