Force Strict Safe Search
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Advanced URL Filtering

Force Strict Safe Search

Table of Contents

Force Strict Safe Search

Follow these steps to enable transparent safe search enforcement on your network.
Where can I use this?
What do I need?
  • Prisma Access (Cloud Management)
  • Prisma Access (Panorama Managed)
  • NGFW (Cloud Managed)
  • NGFW (PAN-OS or Panorama Managed)
Notes:
  • Legacy URL filtering licenses are discontinued, but active legacy licenses are still supported.
  • Prisma Access
    usually include
    Advanced URL Filtering
    capabilities.
You can provide a secure and seamless search experience for Bing and Yahoo end users by transparently enabling strict safe search. Instead of blocking search results when end users search without having enabled strict safe search, the firewall automatically turns on strict safe search and returns only strictly filtered search results. Schools and libraries, for example, can benefit from automatic enforcement that ensures a consistent learning experience.
To activate transparent safe search enforcement, you’ll need to enable Safe Search Enforcement in a URL Filtering profile and replace text in the URL filtering safe search block page file with text provided in the following procedure. The replacement text contains JavaScript that appends search query URLs with strict safe search parameters for the search engine used to search.
The URL filtering safe search block page does not display in the browser.
After completing these steps, the firewall executes the JavaScript whenever an end user searches. For example, suppose a student’s Bing SafeSearch preference is set to
Off
when they research a concept likely to yield inappropriate results. Detecting the safe search preference, the firewall appends
&adlt=strict
to the search query URL. Then, the search engine displays appropriate results and the SafeSearch preference changes to
Strict
.

Cloud Managed

If you’re using Panorama to manage
Prisma Access
:
Toggle over to the
PAN-OS & Panorama
tab and follow the guidance there.
If you’re using
Strata Cloud Manager
, continue here.
  1. Enable Safe Search Enforcement in a URL Access Management profile.
    1. Select
      Manage
      Configuration
      Security Services
      URL Access Management
      .
    2. Under URL Access Management Profiles, select an existing profile or
      Add Profile
      to create a new one. Configuration options appear.
    3. Under
      Settings
      , select
      Safe Search Enforcement
      .
    4. Save
      the profile.
  2. (
    Optional
    ) Restrict the search engines that end users can access.
    1. Select
      Manage
      Configuration
      Security Services
      URL Access Management
      .
    2. Under
      Access Control
      ,
      Search
      ( ) for the
      search-engines
      category.
    3. Set Site Access for the
      search-engines
      category to
      block
      .
      In a later step, you’ll create a custom URL category (URL List type) with the search engines you want to allow.
    4. Save
      the profile.
  3. Apply the URL Access Management profile to Security policy rules that allow traffic from clients in the trust zone to the internet.
    To activate a URL Access Management profile (and any Security profile), add it to
    profile group
    and reference the profile group in a Security policy rule.
  4. Edit the URL Access Management safe search block page, replacing the existing code with JavaScript for rewriting search query URLs.
    1. Select
      Manage
      Configuration
      Security Services
      URL Access Management
      Response Pages
      .
    2. Export HTML Template
      for URL Access Management Block Page.
    3. Use an HTML editor and replace all of the existing block page text with the following text. Then, save the file.
      <html> <head> <title>Search Blocked</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <meta http-equiv="pragma" content="no-cache"> <meta name="viewport" content="initial-scale=1.0"> <style> #content { border:3px solid#aaa; background-color:#fff; margin:1.5em; padding:1.5em; font-family:Tahoma,Helvetica,Arial,sans-serif; font-size:1em; } h1 { font-size:1.3em; font-weight:bold; color:#196390; } b { font-weight:normal; color:#196390; } </style> </head> <body bgcolor="#e7e8e9"> <div id="content"> <h1>Search Blocked</h1> <p> <b>User:</b> <user/> </p> <p>Your search results have been blocked because your search settings are not in accordance with company policy. In order to continue, please update your search settings so that Safe Search is set to the strictest setting. If you are currently logged into your account, please also lock Safe Search and try your search again.</p> <p> For more information, please refer to: <a href="<ssurl/>"> <ssurl/> </a> </p> <p id="java_off"> Please enable JavaScript in your browser.<br></p> <p><b>Please contact your system administrator if you believe this message is in error.</b></p> </div> </body> <script> // Grab the URL that's in the browser. var s_u = location.href; //bing // Matches the forward slashes in the beginning, anything, then ".bing." then anything followed by a non greedy slash. Hopefully the first forward slash. var b_a = /^.*\/\/(.+\.bing\..+?)\//.exec(s_u); if (b_a) { s_u = s_u + "&adlt=strict"; window.location.replace(s_u); document.getElementById("java_off").innerHTML = 'You are being redirected to a safer search!'; } //yahoo // Matches the forward slashes in the beginning, anything, then ".yahoo."" then anything followed by a non greedy slash. Hopefully the first forward slash. var y_a = /^.*\/\/(.+\.yahoo\..+?)\//.exec(s_u); if (y_a) { s_u = s_u.replace(/&vm=p/ig,""); s_u = s_u + "&vm=r"; window.location.replace(s_u); document.getElementById("java_off").innerHTML = 'You are being redirected to a safer search!'; } document.getElementById("java_off").innerHTML = ' '; </script> </html>
  5. Import the edited URL Access Management safe search block page onto the firewall.
    1. Select
      Manage
      Configuration
      Security Services
      URL Access Management
      Response Pages
      .
    2. Click URL Access Management Safe Search Block Page. A dialog appears with a
      Choose File
      option.
    3. Select the safe search block page file you edited earlier and click
      Save
      .
  6. Create a custom URL category for the supported search engines.
    In the next step, you’ll configure the firewall to decrypt traffic to this custom category.
    1. Select
      Manage
      Configuration
      Security Services
      URL Access Management
      .
    2. Under
      Access Control
      , for Custom URL Categories,
      Add Category
      .
    3. Enter a
      Name
      for the category, such as
      SearchEngineDecryption
      .
    4. For
      Type
      of custom URL category, select
      URL List
      .
    5. Under
      Items
      ,
      Add
      the following entries to the URL list:
      • www.bing.*
      • search.yahoo.*
      • yandex.com.*
    6. Save
      the custom category.
    7. Configure Site Access for the new custom URL category.
      1. Under URL Access Management Profiles, select the profile you configured earlier.
      2. Under Access Control, select the new custom URL category. It appears in the Custom URL Categories section above External Dynamic URL Lists and Pre-Defined Categories.
      3. Set
        Site Access
        to
        allow
        .
      4. Save
        your changes.
  7. Because most search engines encrypt their search results, you must enable SSL Forward Proxy decryption so the firewall can inspect the search traffic and detect the safe search settings.
    Under the
    Services and URLs
    section of the Decryption policy rule, click
    Add URL Categories
    . Then, select the custom URL category you created earlier. New custom categories sit at the top of the list.
    Save
    the Decryption policy rule.
  8. Select
    Push Config
    to activate your changes.
  9. Verify the Safe Search Enforcement configuration.
    From a computer behind a firewall, open a browser and perform a search using Bing, Yahoo, or Yandex. Then, use one of the following methods to verify your configuration:
    • Examine the query string of the URL for safe search parameters. Safe Search Settings for Search Providers lists the safe search parameter appended to each search query URL.
    • Go to the safe search settings for a supported search engine and verify that the selected SafeSearch preference is the strictest level (
      Strict
      in most cases).

PAN-OS & Panorama

Configure the strictest Bing and Yahoo SafeSearch settings for end users without requiring manual adjustment of the search engine settings.
  1. Make sure the firewall is running Content Release version 475 or later.
    1. Select
      Device
      Dynamic Updates
      .
    2. Check the
      Applications and Threats
      section to determine what update is currently running.
    3. If the firewall is not running the required update or later, click
      Check Now
      to retrieve a list of available updates.
    4. Locate the required update and click
      Download
      .
    5. After the download completes, click
      Install
      .
  2. Enable Safe Search Enforcement in a URL Filtering profile.
    1. Select
      Objects
      Security Profiles
      URL Filtering
      .
    2. Select an existing profile to modify or clone the default profile to create a new profile.
    3. On the
      URL Filtering Settings
      tab, select
      Safe Search Enforcement
      .
  3. (
    Optional
    ) Restrict the search engines that end users can access in the same URL Filtering profile.
    1. On the
      Categories
      tab,
      Search
      ( ) for the
      search-engines
      category.
    2. Set Site Access for the
      search-engines
      category to
      block
      .
      In a later step, you’ll create a custom URL category (URL List type) with the search engines you want to allow.
    3. Click
      OK
      to save the profile.
  4. Apply the URL Filtering profile to Security policy rules that allow traffic from clients in the trust zone to the internet.
    1. Select
      Policies
      Security
      . Then, click the rule to which you want to apply the URL Filtering profile.
    2. On the
      Actions
      tab, find Profile Setting. For
      Profile Type
      , select
      Profiles
      . A list of profiles appears.
    3. For the
      URL Filtering
      profile, select the profile you created earlier.
    4. Click
      OK
      to save the Security policy rule.
  5. Edit the URL filtering safe search block page, replacing the existing code with JavaScript for rewriting search query URLs.
    1. Select
      Device
      Response Pages
      URL Filtering Safe Search Block Page
      .
    2. Select
      Predefined
      and then click
      Export
      to save the file locally.
    3. Use an HTML editor and replace all of the existing block page text with the following text. Then, save the file.
      <html> <head> <title>Search Blocked</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <meta http-equiv="pragma" content="no-cache"> <meta name="viewport" content="initial-scale=1.0"> <style> #content { border:3px solid#aaa; background-color:#fff; margin:1.5em; padding:1.5em; font-family:Tahoma,Helvetica,Arial,sans-serif; font-size:1em; } h1 { font-size:1.3em; font-weight:bold; color:#196390; } b { font-weight:normal; color:#196390; } </style> </head> <body bgcolor="#e7e8e9"> <div id="content"> <h1>Search Blocked</h1> <p> <b>User:</b> <user/> </p> <p>Your search results have been blocked because your search settings are not in accordance with company policy. In order to continue, please update your search settings so that Safe Search is set to the strictest setting. If you are currently logged into your account, please also lock Safe Search and try your search again.</p> <p> For more information, please refer to: <a href="<ssurl/>"> <ssurl/> </a> </p> <p id="java_off"> Please enable JavaScript in your browser.<br></p> <p><b>Please contact your system administrator if you believe this message is in error.</b></p> </div> </body> <script> // Grab the URL that's in the browser. var s_u = location.href; //bing // Matches the forward slashes in the beginning, anything, then ".bing." then anything followed by a non greedy slash. Hopefully the first forward slash. var b_a = /^.*\/\/(.+\.bing\..+?)\//.exec(s_u); if (b_a) { s_u = s_u + "&adlt=strict"; window.location.replace(s_u); document.getElementById("java_off").innerHTML = 'You are being redirected to a safer search!'; } //yahoo // Matches the forward slashes in the beginning, anything, then ".yahoo."" then anything followed by a non greedy slash. Hopefully the first forward slash. var y_a = /^.*\/\/(.+\.yahoo\..+?)\//.exec(s_u); if (y_a) { s_u = s_u.replace(/&vm=p/ig,""); s_u = s_u + "&vm=r"; window.location.replace(s_u); document.getElementById("java_off").innerHTML = 'You are being redirected to a safer search!'; } document.getElementById("java_off").innerHTML = ' '; </script> </html>
  6. Import the edited URL filtering safe search block page onto the firewall.
    1. Select
      Device
      Response Pages
      URL Filtering Safe Search Block Page
      .
    2. Click
      Import
      . Then,
      Browse
      for the block page file or enter the path and filename in the
      Import File
      field.
    3. (
      Optional
      ) For
      Destination
      , select either the virtual system on which the login page will be used or
      shared
      to make it available to all virtual systems.
    4. Click
      OK
      to import the file.
  7. Create a custom URL category for the supported search engines.
    In the next step, you’ll configure the firewall to decrypt traffic to this custom category.
    1. Select
      Objects
      Custom Objects
      URL Category
      and
      Add
      a custom category.
    2. Enter a
      Name
      for the category, such as
      SearchEngineDecryption
      .
    3. Add
      the following entries to the
      Sites
      list:
      • www.bing.*
      • search.yahoo.*
      • yandex.com.*
    4. Click
      OK
      to save the custom URL category.
  8. Because most search engines encrypt their search results, you must enable SSL Forward Proxy decryption so the firewall can inspect the search traffic and detect the safe search settings.
    On the
    Service/URL Category
    tab of the Decryption policy rule,
    Add
    the custom URL category you created earlier. Then, click
    OK
    .
  9. Commit
    your changes.
  10. Verify the Safe Search Enforcement configuration.
    From a computer behind a firewall, open a browser and perform a search using Bing or Yahoo. Then, use one of the following methods to verify your configuration works as intended:
    • Examine the query string of the URL for safe search parameters. Safe Search Settings for Search Providers lists the safe search parameter appended to each search query URL.
    • Go to the Safe Search settings for the search engine and verify that the selected SafeSearch preference is the strictest level (
      Strict
      in the case of Bing).

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