IIS – How to setup the web.config file to send HTTP Security Headers with your web site (and score an A on securityheaders.io)

IIS - How to setup the web.config file to send HTTP Security Headers with your web site (and score an A on securityheaders.io)

We already explained the basics about HTTP Security Headers in this previous post: it’s now time to put all these words into action and learn how we can implement them within our Internet Information Services (IIS) instance to shield our valuable web sites from most dangerous threats. In case you need to do that with an Apache web server, read here.

The first thing we should do is check our website before making any change, to get a grip of how things currently are. Here are some websites that we can use to scan our web site:

Our personal favourite is the first one, as it also has a nice rating system that might help us to understand how protected we are (or not). If your website has no security headers, you’ll most likely end up with a severe F rating, just like the following screenshot:

IIS - How to setup the web.config file to send HTTP Security Headers with your web site (and score an A on securityheaders.io)

We know, this is our site! We temporarily deactivated everything to be able to get a screenshot that could show the worst possible outcome. If that’s your scenario as well, don’t worry: you’re 1 minute away from ranking up to A !

Without further ado, here’s the relevant snippet to place within your application’s   file:

That’s about it. These settings are loose enough for most web sites while keeping a strong level of security: you shouldn’t have issues with any standard website based upon WordPress, Joomla, Drupal, ASP.NET Core MVC and so on.

In case you need a more relaxed content security policy – for example, if you have media, applets or unsafe scripts & styles – you can tweak that specific line. Here’s an example accepting basically everything:

Don’t get us wrong, we’re not suggesting using it in any way! However, whenever a given scenario would force us to accept anything, having a super-permissive policy it’s still better than having none.

And here’s our scan after implementing all of the above:

IIS - How to setup the web.config file to send HTTP Security Headers with your web site (and score an A on securityheaders.io)

That’s it! If you need to do that with Apache, read here.

I sincerely hope that this post will help you to improve the security level of your web site as well.

 

 

 

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About Ryan

IT Project Manager, Web Interface Architect and Lead Developer for many high-traffic web sites & services hosted in Italy and Europe. Since 2010 it's also a lead designer for many App and games for Android, iOS and Windows Phone mobile devices for a number of italian companies.

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