Details

A browser extension is a program that has been installed into the browser to add functionality. Where a plug-in interacts only with a web page and usually a third-party external application (e.g., Flash, Adobe Reader), an extension interacts with the browser program itself. Extensions are not embedded in web pages and must be downloaded and installed in order to work. Extensions allow browsers to avoid restrictions that apply to web pages.

For example, an extension can be written to combine data from multiple domains and present it when a certain page is accessed, which can be considered cross-site scripting. If a browser is configured to allow unrestricted use of extensions, plug-ins can be loaded and installed from malicious sources and used on the browser.

Solution

Windows group policy:
1. Open the group policy editor tool with ‘gpedit.msc’.
2. Navigate to Policy Path: Computer ConfigurationAdministrative TemplatesMozillaFirefoxAddons
Policy Name: Allow add-on installs from websites
Policy State: Disabled

macOS ‘plist’ file:
Add the following:
InstallAddonsPermission

Linux ‘policies.json’ file:
Add the following in the policies section:
‘InstallAddonsPermission’: false

Supportive Information

The following resource is also helpful.

• https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_MOZ_Firefox_V6R1_STIG.zip

This security hardening control applies to the following category of controls within NIST 800-53: Configuration Management.This control applies to the following type of system Unix.

References

• 800-53|CM-7a.
• CAT|II
• CCI|CCI-000381
• Rule-ID|SV-251557r807143_rule
• STIG-ID|FFOX-00-000013
• Vuln-ID|V-251557

Source

• Tenable.com/audits