Firefox must be configured so that DNS over HTTPS is disabled.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-251577	FFOX-00-000033	SV-251577r807203_rule		Medium

Description
DNS over HTTPS has generally not been adopted in the DoD. DNS is tightly controlled. It is detrimental for applications to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Applications are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include, but are not limited to, advertising software or browser plug-ins not related to requirements or providing a wide array of functionality not required for every mission, but cannot be disabled.

Description

DNS over HTTPS has generally not been adopted in the DoD. DNS is tightly controlled. It is detrimental for applications to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Applications are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include, but are not limited to, advertising software or browser plug-ins not related to requirements or providing a wide array of functionality not required for every mission, but cannot be disabled.

STIG	Date
Mozilla Firefox Security Technical Implementation Guide	2021-12-01

Details

Check Text ( C-55012r807201_chk )
Type "about:policies" in the browser address bar. If "DNSOverHTTPS" is not displayed under Policy Name or the Policy Value does not have "Enabled" with a value of "false", this is a finding.

Fix Text (F-54966r807202_fix)
Windows group policy: 1. Open the group policy editor tool with "gpedit.msc". 2. Navigate to Policy Path: Computer Configuration\Administrative Templates\Mozilla\Firefox\DNS Over HTTPS Policy Name: Enabled Policy State: Disabled macOS "plist" file: DNSOverHTTPS Enabled Linux "policies.json" file: Add the following in the policies section: "DNSOverHTTPS": {"Enabled": false}