How to deny webex in a browser via SG proxy

Products

• ASG-S200
• ASG-S400
• ASG-S500
• ISG Proxy
• ProxySG Software - SGOS
• SG-S500
• SG-S400
• SGVA

Issue/Introduction

You want to block user from from accessing webex via browser and force them to only use a desktop application.

Cause

Due to security reasons and controlling capabilities some environments requires webex web client from running on browsers.
Instead of having choose option:

There will be only one option that will run desktop webex app:

Resolution

In order to achieve this it is necessary to block javascript called thinClientSupportAPI.js coming from webex domain.

1. In order to this it is required to enable ssl interception to see full url path.

As you can see in screenshot below, ssl interception for webex.com domain is enabled

2. Then in web access layer I used regex expression to block/deny the url path to the javascript.
Regex expression:
[a-z0-9]*.*thinClientSupportAPI\.js[az0-9\.=\?]*

3. Once we installed this policy we could clearly see that the rule is matching in policy trace and the browser join option is gone.