Firefox must be configured to ask which certificate to present to a website when a certificate is required.

Severity
Group ID
Group Title
Version
Rule ID
Date
STIG Version
mediumV-251547SRG-APP-000177FFOX-00-000003SV-251547r1067550_rule2025-02-116
Description
When a website asks for a certificate for user authentication, Firefox must be configured to have the user choose which certificate to present. Websites within DOD require user authentication for access, which increases security for DOD information. Access will be denied to the user if certificate management is not configured.
ℹ️ Check
Type "about:policies" in the browser address bar. If "Preferences" is not displayed under Policy Name and the Policy Value does not include "security.default_personal_cert" with a value of "Ask Every Time" and status of "locked", 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: Preferences Policy State: Enabled Policy Value: { "security.default_personal_cert": { "Value": "Ask Every Time", "Status": "locked" } } macOS "plist" file: Add the following: <key>Preferences</key> <dict> <key>security.default_personal_cert</key> <dict> <key>Value</key> <string>Ask Every Time</string> <key>Status</key> <string>locked</string> </dict> </dict> Linux "policies.json" file: Add the following in the policies section: "Preferences": { "security.default_personal_cert": { "Value": "Ask Every Time", "Status": "locked" } }