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V-251555

CAT II (Medium)

Firefox must be configured to prevent JavaScript from raising or lowering windows.

Rule ID

SV-251555r1067556_rule

STIG

Mozilla Firefox Security Technical Implementation Guide

Version

V6R7

CCIs

CCI-000381

Discussion

JavaScript can raise and lower browser windows to cause improper input. Configure the browser setting to prevent scripts on visited websites from raising and lowering browser windows.

Check Content

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

If "Preferences" is not displayed under Policy Name or the Policy Value does not include "dom.disable_window_flip" with a value of "true" and status of "locked", this is a finding.

Fix Text

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:
{
  "dom.disable_window_flip": {
    "Value": true,
    "Status": "locked"
  }
}

macOS "plist" file:
Add the following:
<key>Preferences</key>
<dict>
  <key>dom.disable_window_flip</key>
  <dict>
    <key>Value</key>
    <true/>
    <key>Status</key>
    <string>locked</string>
  </dict>
</dict>

Linux "policies.json" file:
Add the following in the policies section:
"Preferences": {
  "dom.disable_window_flip": {
    "Value": true,
    "Status": "locked"
  }
}