Firefox must be configured to block pop-up windows.

An XCCDF Rule

Description

<VulnDiscussion>Pop-up windows may be used to launch an attack within a new browser window with altered settings. This setting blocks pop-up windows created while the page is loading.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>

ID: SV-251553r879587_rule
Severity: Medium
References: CCI-000381
Updated: about 1 year ago

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}

Firefox must be configured to block pop-up windows.

Description

Remediation - Manual Procedure