How secure is my MVC5 application.

Hell All,

I have created an MVC 5 tutorial. I just followed the steps in this tutorial :

http://www.asp.net/mvc/overview/getting-started/getting-started-with-ef-using-mvc/creating-an-entity-framework-data-model-for-an-asp-net-mvc-application

My website has default individual user accounts. I haven't done anything extra for security.

I'd like to know how secure is my application. What else should I do to make sure my app is secure?

Thanks in advance.