Firefox private browsing must be disabled.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-251563	SRG-APP-000141	FFOX-00-000019	SV-251563r960963_rule	2025-02-11	6

Description
Private browsing allows the user to browse the internet without recording their browsing history/activity. From a forensics perspective, this is unacceptable. Best practice requires that browser history is retained.

ℹ️ Check
Type "about:policies" in the browser window. If "DisablePrivateBrowsing" is not displayed under Policy Name or the Policy Value is not "true", this is a finding.

✔️ 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 Policy Name: Disable Private Browsing Policy State: Enabled macOS "plist" file: Add the following: <key>DisablePrivateBrowsing</key> <true/> Linux "policies.json" file: Add the following in the policies section: "DisablePrivateBrowsing": true

✔️ 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 Policy Name: Disable Private Browsing Policy State: Enabled macOS "plist" file: Add the following: <key>DisablePrivateBrowsing</key> <true/> Linux "policies.json" file: Add the following in the policies section: "DisablePrivateBrowsing": true