How to use ProxySG policy to block Google search filters

Products

• ProxySG Software - SGOS

Issue/Introduction

Users can perform a Google web search and then filter results by images, video, and other criteria. You want to block Google image and video search, but policy gets circumvented when users filter the search; the page is not denied.

 

Resolution

Instead of using the path in the URL to define if the client is doing a web, images, video, etc search, Google is using a parameter called tbm.

Instead of

http://www.google.ca/webhp?hl=en&tab=ww#hl=en..................
 

For example, starting with the default web search and then clicking a tab to filter results yields the following URL:

• Video search: https://www.google.com/search?q=google&biw=1600&bih=777&source=lnms&tbm=vid&sa=X&ved=0ahUKEwj98fbbxu_MAhVJw2MKHRNgDBEQ_AUIBygC 
• Image search: https://www.google.com/search?q=google&biw=1600&bih=777&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj98fbbxu_MAhVJw2MKHRNgDBEQ_AUICSgE 
• Shopping search: https://www.google.com/search?q=google&biw=1600&bih=777&source=lnms&tbm=shop&sa=X&ved=0ahUKEwiXhKHuyO_MAhVJ02MKHUPoAG0Q_AUIDCgA   

You must write policy to block URLs with  "tbm=" combined with Google domains.

Example 1:
 

<Proxy>  ; Block searching from tabs

url.domain=google.com url.regex="tab="

Example 2:
<Proxy>  ;Block searching video and images tabs

url.domain=google.com url.regex="tab=vid" Deny
url.domain=google.com url.regex="tab=isch" Deny