Firefox must be configured to not automatically check for updated versions of installed search plugins.

Updates must be controlled and installed from authorized and trusted servers. This setting overrides a number of other settings that may direct the application to access external URLs.

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

If "Preferences" is not displayed under Policy Name or the Policy Value does not include "browser.search.update" with a value of "false" and status of "locked", this is a finding.

Windows group policy: 1. Open the group policy editor tool with "gpedit.msc". 2. Navigate to Policy Path: Computer Configuration\Administrative Templates\Mozilla\Firefox\ Policy Name: Preferences Policy State: Enabled Policy Value: { "browser.search.update": { "Value": false, "Status": "locked" } }

macOS "plist" file: Add the following: <key>Preferences</key> <dict> <key>browser.search.update</key> <dict> <key>Value</key> <false/> <key>Status</key> <string>locked</string> </dict> </dict>

Linux "policies.json" file: Add the following in the policies section: "Preferences": { "browser.search.update": { "Value": false, "Status": "locked" } }