Skip to main content

Impersonation in ASP.NET Core

A colleague reached out to me with a specific scenario he had to tackle. He had an IIS hosted ASP.NET Core application using Windows Authentication where he had to execute a specific action on behalf of the current user. The typical way to do this is through impersonation. In this post I’ll explain what impersonation is and how you can get this working in ASP.NET Core.

What is impersonation?

Impersonation is a security feature that allows an application to execute code under the context of a different user identity. This capability is often used when an application needs to access resources, such as files, databases, or network services, with permissions different from those of the current user or the application's process.

By using impersonation the application temporarily assumes the identity of another user to perform specific actions, reverting back to its original identity afterward.

Some common use cases for impersonation are:

  • Accessing network shares or file systems with restricted permissions.

  • Performing administrative tasks that require elevated privileges.

  • Connecting to databases using Windows Authentication.

Impersonation in ASP.NET Core

In classic ASP.NET, impersonation could be enabled through the web.config file. However, ASP.NET Core does not support this configuration-based impersonation. Instead, impersonation must be handled programmatically using the use WindowsIdentity.RunImpersonated or RunImpersonatedAsync.

Here’s a basic example demonstrating how to implement impersonation in an ASP.NET Core application:

Remark: In the example above we are using middleware to run our impersonated code but you can also use an action filter if you want(Let me know if I should add an example).

Make sure that when trying the code above that you have the following configuration set in IIS:

  • Enable Windows Authentication in IIS Manager.

  • Disable Anonymous Authentication if not required.

  • Ensure the application pool identity has the necessary permissions for delegation if needed.

More information

Configure Windows Authentication in ASP.NET Core | Microsoft Learn

Labels:

Popular posts from this blog

Podman– Command execution failed with exit code 125

After updating WSL on one of the developer machines, Podman failed to work. When we took a look through Podman Desktop, we noticed that Podman had stopped running and returned the following error message: Error: Command execution failed with exit code 125 Here are the steps we tried to fix the issue: We started by running podman info to get some extra details on what could be wrong: >podman info OS: windows/amd64 provider: wsl version: 5.3.1 Cannot connect to Podman. Please verify your connection to the Linux system using `podman system connection list`, or try `podman machine init` and `podman machine start` to manage a new Linux VM Error: unable to connect to Podman socket: failed to connect: dial tcp 127.0.0.1:2655: connectex: No connection could be made because the target machine actively refused it. That makes sense as the podman VM was not running. Let’s check the VM: >podman machine list NAME         ...
Read more

Azure DevOps/ GitHub emoji

I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup: All credits go to rcaviers who created this list.
Read more

VS Code Planning mode

After the introduction of Plan mode in Visual Studio , it now also found its way into VS Code. Planning mode, or as I like to call it 'Hannibal mode', extends GitHub Copilot's Agent Mode capabilities to handle larger, multi-step coding tasks with a structured approach. Instead of jumping straight into code generation, Planning mode creates a detailed execution plan. If you want more details, have a look at my previous post . Putting plan mode into action VS Code takes a different approach compared to Visual Studio when using plan mode. Instead of a configuration setting that you can activate but have limited control over, planning is available as a separate chat mode/agent: I like this approach better than how Visual Studio does it as you have explicit control when plan mode is activated. Instead of immediately diving into execution, the plan agent creates a plan and asks some follow up questions: You can further edit the plan by clicking on ‘Open in Editor’: ...
Read more