STIGQter: STIG Summary: Mozilla Firefox Security Technical Implementation Guide Version: 6 Release: 8 Benchmark Date: 01 Jul 2026:

Firefox must be configured to block pop-up windows.

DISA Rule

SV-251553r960963_rule

Vulnerability Number

V-251553

Group Title

SRG-APP-000141

Rule Version

FFOX-00-000009

Severity

CAT II

CCI(s)

CCI-000381 - Configure the system to provide only organization-defined mission essential capabilities.

Weight

Fix Recommendation

Windows group policy:
1. Open the group policy editor tool with "gpedit.msc".
2. Navigate to Policy Path: Computer Configuration\Administrative Templates\Mozilla\Firefox\Popups
Policy Name: Block pop-ups from websites
Policy State: Enabled

Policy Name: Do not allow preferences to be changed
Policy State: Enabled

Optional:
Policy Name: Allowed Sites
Policy State: Enabled
Click "Show..." and enter a list of websites to be allowlisted.

macOS "plist" file:
Add the following:
<key>PopupBlocking</key>
<dict>
<key>Allow</key>
<array>
<string>http://example.mil</string>
<string>http://example.gov</string>
</array>
<key>Default</key>
<true/>
<key>Locked</key>
<true/>
</dict>

Linux "policies.json" file:
Add the following in the policies section:
"PopupBlocking": {
"Allow": ["http://example.mil/",
"http://example.gov/"],
"Default": true,
"Locked": true}

Check Contents

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

If "PopupBlocking" is not displayed under Policy Name or the Policy Value is not "Default" "true", this is a finding.
If "PopupBlocking" is not displayed under Policy Name or the Policy Value is not "Locked" "true", this is a finding.

"PopupBlocking" "Enabled" may be used to specify an allowlist of sites where pop-ups are desired, this is optional.

Vulnerability Number

V-251553

Documentable

False

Rule Version

FFOX-00-000009

Severity Override Guidance

Check Content Reference

Target Key

5446