How to secure the internet side of your Citrix Netscaler

This is a two-minute guide to securify the internet side of your Netscaler. We will setup two parameters, the “Deny SSL Renegotiation” and the acceptable Ciphers.

A. Deny SSL Renegotiation

Go to Traffic Management – SSL page on your netscaler and press the “Change Advanced SSL Settings” link.

Change advanced SSL Settings

Change advanced SSL Settings

The advanced SSL settings will appear. Notice that the default value of “Deny SSL Renegotiation” property is “NO”. Change it to “FRONTEND_CLIENT”.

Deny SSL Renegotiation

Deny SSL Renegotiation

You may want to change it to the strict value “ALL” depending on your web farm structure. This setting is usually a finding after a penetration test, so set it up to avoid SSL Renegotiation Denial of Service attacks.

B. Configure the Cipher Group

Go to the SSL tab in your virtual server and select Ciphers. The configured Cipher Group is called “DEFAULT” and includes 128bit strength ciphers. Remove this value and in the available Cipher Groups pane, select “HIGH”. This group includes high strength 168bit encryption ciphers. The available ciphers pane lists the acceptable ciphers of the selected group.

All modern browser are compatible with these ciphers, so go ahead and use them.

Cipher Groups

Cipher Groups

Do the same for all your virtual servers.

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