Stop Sharing Cookies between Applications under same Site ID in IIS - iis

Question

The issue I have is we currently are using IdentityServer as our SSO authentication for our corporate applications. However, the bulk of our applications are under the same Site ID in IIS 7.5. When navigating to more than 5 of these applications under the same Site ID, you end up getting a 400 error, request header too long. The reason being each application has its own cookie, so the request header is passing around 5+ cookies with token information and the becoming too large.
My question is, are you able to prevent the sharing of cookies between applications under the same Site ID in IIS 7.5?

Answer 1

We also have IdentityServer for SSO and internal applications hosted on the same machine on IIS.
And I faced with the same problem too.
Here is a solution:
1) You need to solve Owin/Katana middleware problem to avoid nonce overfloating. Here you can find the code for that fix
2) You have to stop sharing cookies.
So if your base address for applications is "mysite.com".
And you have a lot of different applications like this:
Good App: mysite.com/good_app/
Best App: mysite.com/best_app/
Super App: mysite.com/super_app/
Use CookiePath for each application on an application's side and it will limit cookies (and look here too).
Use the code like this (for "Good App"):
var cookieOptions = new CookieAuthenticationOptions
{
AuthenticationType = "Cookies",
CookieName = "GoodAppCookies",
// Cookie Path same as application name on IIS
CookiePath = "/good_app
};
Hope it'll help.

Answer 2

Few things that you can try. Make the following changes at the server level.
Highlight the server name in IIS, select "configuration editor", select "system.web" and "httpRuntime" and change "maxRequestLength" to "1048576".
You can also edit the "applicationHost.config" file in the following way- C:\Windows\System32\inetsrv\Config
<configuration>
<system.web>
<httpRuntime maxRequestLength="1048576" />
</system.web>
</configuration>
Edit "Request Filtering" settings at server level on IIS and set "maxAllowedContentLength" to "1073741824"
You can also edit the root web.config file in the following manner - C:\Windows\Microsoft.NET\Framework64*\v4.0.30319*\Config
*Folder is based on your application. if its a 32 bit application, navigate to "Framework" folder. If its a .net 2.0 application, navigate to v2.0.50727.
<system.webServer>
<security>
<requestFiltering>
<requestLimits maxAllowedContentLength="1073741824" />
</requestFiltering>
</security>
</system.webServer>

Answer 3

First of all - I want to say that I have not tried this myself, so I can't assure that it is a solution, but I'm trying to help.
The problem with the cookies originates from the Microsoft OWIN/Katana and the way they are encrypting them. They become enormous, but this has nothing to do with Identity Server. However here and here there are good discussion around this.
The main thing to try first is in the Startup.cs of the IdentityServer project, in the IdentityServerOptions.AuthenticationOptions there is a property SignInMessageThreshold which defaults to 5. Try setting it to something lower, this will keep your header smaller (which may cause round trips to identity server when an app doesn't have its message in the cookies, but this will not force the user to re-login).
Another thing, that we achieved in one of out projects, is to create a DataBase backed cookie session handler. In your clients, where you use
app.UseCookieAuthentication(new CookieAuthenticationOptions
{
AuthenticationType = "Cookies",
CookieName = cookieName,
});
There is also a property SessionStore. You can have a custom implementation of the Microsoft.Owin.Security.Cookies.IAuthenticationSessionStore. In our case this reduced the cookie size to less than (or around) 300.