Azure Service authentication in Visual Studio 2022 works even after sign out

I'm working on an ASP.NET Core Web API project. In this project I'm using Azure.Security.KeyVault.Secrets's SecretClient class to fetch secrets from a key vault.

I'm able to fetch the secrets from key vault when I signed in into Visual Studio using my personal Microsoft account as well as without sign in into Visual Studio. I wanted to know how SecretClient class authenticates the user? How it is able to get Azure AD token to authenticate itself with Azure key vault to retrieve secret even without signing into Visual Studio?

Below is the code I have used in Program.cs (.NET 6) file to inject the SecretClient dependency:

using backendapp.Services.Contracts;
using backendapp.Services;
using Microsoft.Extensions.Azure;
using backendapp.Services.Repository;

namespace backendapp;

public class Program
{
    public static void Main(string[] args)
    {
        var builder = WebApplication.CreateBuilder(args);

        // Add services to the container.

        builder.Services.AddControllers();
        // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
        builder.Services.AddEndpointsApiExplorer();
        builder.Services.AddSwaggerGen();
        builder.Services.AddAzureClients(azureClientFactoryBuilder =>
        {
            azureClientFactoryBuilder.AddSecretClient(builder.Configuration.GetSection("KeyVault"));
        });
        builder.Services.AddSingleton<IKeyVaultManager, KeyVaultManager>();
        builder.Services.AddSingleton<IDocumentClientWrapper, DocumentClientWrapper>();
        builder.Services.AddSingleton<IDbManager, DbManager>();
        builder.Services.AddSingleton<IEmployeeRepository, EmployeeRepository>();

        var app = builder.Build();

        // Configure the HTTP request pipeline.
        if (app.Environment.IsDevelopment())
        {
            app.UseSwagger();
            app.UseSwaggerUI();
        }

        app.UseHttpsRedirection();

        app.UseAuthorization();

        app.MapControllers();

        app.Run();
    }
}

Also in appsettings.json, I have a section KeyVault which has just a VaultUri entry.

Below is my KeyVaultManager class which uses the SecretClient class

    public class KeyVaultManager : IKeyVaultManager
    {
        private SecretClient _secretClient;

        public KeyVaultManager(SecretClient secretClient)
        {
            _secretClient = secretClient;
        }

        public async Task<string> GetSecretAsync(string secretName)
        {
            try
            {
                KeyVaultSecret keyVaultSecret = await _secretClient.GetSecretAsync(secretName);
                return keyVaultSecret.Value;
            }
            catch(Exception ex)
            {
                throw;
            }
        }
    }

I wanted to know how I'm able to fetch secrets from keyvault under my personal account even without signing in to Visual Studio.

Azure authentication utilizes various methods to authenticate with Azure services, attempting them in a specific order.

You can check out the AzureDefaultCredentials documentation to see the different mechanisms and the sequence in which they are tried.

It is very likely that you are still logged in with Azure Cli.