ExtRSAuth for Custom SSRS Authentication (works w/newest SSRS version 16.0.8)

Fortunately, ExtRSAuth code doesn't require any updates to work with MSSQL SSRS 2022

ExtRSAuth for custom SSRS security 

This assembly, forked from the Microsoft Custom Security Sample extends and improves custom authentication to allow for mechanisms other than user/pwd credential check and to offer a seamless pass-thru of the Login page if something present in the HttpRequest verifies that user is already authenticated. For instance, the user already has an app token from an app that communicates with the report server, and you require the communications with the report server to not involve any intermediate screen or login UI. The user just wants to auth as fast as possible and get to their report, right?

What does ExtRSAuth do to authenticate SSRS user connections?

For direct URL report server access, the default here is to allow local connections, which grants Admin rights for any local requests. If the SSRS request is external, a fallback option accepts an AES 128-bit encrypted querystring from the calling app, and the application, if decryption works, is authenticated and allowed to communicate using a read-only SSRS user; any exception thrown indicates the request is neither from a local connection nor a secure request from the external app.

ExtRSAuth gives SSRS environments the freedom from MS Active Directory that they deserve

To secure the built-in SSRS REST API v2.0 access, you can simply customize the LogonUser() and VerifyPassword() methods in AutneticationExtension.cs and AuthenticationUtilities.cs, respectively:

If you don't perform a security check here, the SSRS REST API will be open to anyone who knows the SSRS admin username

As you can see, this is but one of many approaches we can take with ExtRSAuth in an SSRS-connected application or business environment. Any type and granularity of custom authentication and level of authorization is possible. The only ingredient needed is a .NET developer or developers willing to customize a pretty basic .NET security model.

Real-world applications

This Custom Auth assembly has been tested with (1) several .NET Framework 4.8 and .NET 5, 6, 7 and 8 web and mobile applications, (2) with the SSRS API and all its operations, (3) with the SSRS /ReportServer and the /Reports management web interface as well as (4) Visual Studio 2022 Reporting Services projects (report designers can seamlessly deploy Report Server projects from VS to the Report Server with ExtRSAuth).

After running InitalizeExtRSAuth.ps1, a successful installation will output the above

Demonstration

This YouTube explainer video describes the SSRS external user authentication problem that ExtRSAuth addresses.

Requirements

This plug-in relies on SSRS (2016 or later), and a report server configuration as described in Microsoft's Reporting Services Custom Security Sample

-Replace [your_sym_encr_key] with your symmetric encryption key. Clients can encrypt SSRS URL access querystring with Sonrai.ExtRSAuth.Excryption.Encrypt() or a similar 128-bit AES encryption implementation, or modify Encrypt() with any encryption algorithm and key and block sizes.

Clone it, customize it further (or not) and get started today: https://github.com/sonrai-LLC/ExtRSAuth

Custom SSRS Authentication Extended

One of the limitations of SSRS is that it cannot be used outside of a Windows environment (security is all dependent on Active Directory and Windows User accounts). Unfortunately app impersonation does not work cleanly enough as it will prompt users for credentials when they 1st authenticate to the Report Server. That doesn't cut the mustard for user expectations of public-facing apps.

Authentication only works as far its interoperability can reach (needs to reach beyond Windows Auth)

So, to get around this, Microsoft has provided a workaround in the form of the CustomAuthentication example. It provides a basic way to authenticate using forms-based authentication with a login page. This does work, "technically". But this also will not work if we want our report authentication to be invisible/seamless to a user who is already authenticated to the main app (that provides SSRS-based reporting features).

Why make a user auth 2x? 

So.... (and this isn't incredibly clever but it's useful): enter this extension of the CustomAuthentication example that is Local-only access by default, but suggests several overrides for authentication.

Here is the crux of how the CustomAuth can work in many different ways simply via modifying Login.aspx.cs of the Microsoft example:

        private void Page_Load(object sender, EventArgs e)
        {
            //Your secret authentication sauce goes here..
            //appHash should get dynamically generated from the app calling SSRS (ideally for each request if performant enough)
            //ie. 
            //if (CheckAuth(System.Web.HttpContext.Current.Request.Cookies["origAppHash"].ToString()))
            //if (CheckAuth(System.Web.HttpContext.Current.Session["otroAppHash"].ToString()))
            if (System.Web.HttpContext.Current.Request.IsLocal)
                FormsAuthentication.RedirectFromLoginPage("daylite", true);
        }

        private bool CheckAuth(string appHash)
        {
            //DecodeAndCryptoChecks on appHash
            return true;
        }

 MS' Example uses Page_Load(); presumably Page_PreLoad() or Page_Init() would also work here- 'just an HttpRequest eval

The idea behind this branch (closed as soon as PR'd as I don't expect MS to integrate this but I did want to not-so-subtly nudge them to explain SSRS' custom extensibility better) is not a defined solution- it is to demonstrate how you can interface with the authentication and authorization operations of SSRS service to achieve virtually any kind of custom security behavior or compatibility that you require.

GitHub (my sonrai LLC is my contractor/consultant LLC): https://github.com/sonrai-LLC/ExtRSAuth