Firefox must be configured to not delete data upon shutdown.

For diagnostic purposes, data must remain behind when the browser is closed. This is required to meet non-repudiation controls.

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

If "SanitizeOnShutdown" is not displayed under Policy Name or the Policy Value does not have {"Cache":false,"Cookies":false,"Downloads":false,"FormData":false,"Sessions":false,"History":false,"OfflineApps":false,"SiteSettings":false,"Locked":true}, 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\Clear data when browser is closed Policy Name: Cache, Cookies, Download History, Form & Search History, Browsing History, Active Logins, Site Preferences, Offline Website Data Policy State: Disabled Policy Name: Locked Policy State: Enabled

macOS "plist" file: Add the following: <key>SanitizeOnShutdown</key> <dict> <key>Cache</key> <false/> <key>Cookies</key> <false/> <key>Downloads</key> <false/> <key>FormData</key> <false/> <key>History</key> <false/> <key>Sessions</key> <false/> <key>SiteSettings</key> <false/> <key>OfflineApps</key> <false/> <key>Locked</key> <true/> </dict>

Linux "policies.json" file: Add the following in the policies section: "SanitizeOnShutdown": { "Cache": false, "Cookies": false, "Downloads": false, "FormData": false, "History": false, "Sessions": false, "SiteSettings": false, "OfflineApps": false, "Locked": true }