SV-251572r960963: Firefox must not recommend extensions as the user is using the browser. | Mozilla Firefox for Linux STIG SCAP Benchmark

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Assessment Title

Rule Text

Firefox must not recommend extensions as the user is using the browser.

Description

Discussion Text

The Recommended Extensions program recommends extensions to users as they surf the web. The user must not be encouraged to install extensions from the websites they visit. Allowed extensions are to be centrally managed.

How this relates to the STIG checklist: STIG vs SCAP benchmark.

IA Controls

NIST SP 800-53

Not mappedCCI-000381

References

DPMS Target Mozilla Firefox 2021 VERSION DISA DPMS Target Mozilla Firefox 2021 VERSION 5446

Checks

DISA STIG (Manual Reference)

Type "about:policies" in the browser address bar. 

If "UserMessaging" is not displayed under Policy Name or the Policy Value is not "ExtensionRecommendations" with a value of "false", this is a finding.

SCC Automation Reference

The reconstructed evaluation script behind this rule's OVAL check(s) — every module a compound check combines, with this rule's own concrete values and DISA's SCC tool's real per-module mechanism curated from static teardown of SCC releases.

#!/bin/bash
# Reconstructed from oval:mil.disa.stig.firefox.linux:def:127
# Firefox must not recommend extensions as the user is using the browser.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.
#
# MANUAL REVIEW REQUIRED -- the module(s) below could not be reconstructed
# into working code from curated SCC reference data, and are excluded from
# the automated result:
#   - textfilecontent54_object (textfilecontent54_test) -- UserMessaging ExtensionRecommendations set to false: no extractor for field "subexpression"

echo "MANUAL REVIEW REQUIRED -- see notes above; no part of this check could be automated"

Remediation

Windows group policy:
1. Open the group policy editor tool with "gpedit.msc".
2. Navigate to Policy Path: Computer Configuration\Administrative Templates\Mozilla\Firefox\User Messaging
Policy Name: Extension Recommendations
Policy State: Disabled

macOS "plist" file:
Add the following:
<key>UserMessaging</key>
<dict>
  <key>ExtensionRecommendations</key>
  <false/>
</dict>

Linux "policies.json" file:
Add the following in the policies section:
"UserMessaging": {
  "ExtensionRecommendations": false
}