ASP.NET Core Authorize attribute not working with JWT
<p>I want to implement JWT-based security in ASP.Net Core. All I want it to do, for now, is to read bearer tokens in the <code>Authorization</code> header and validate them against my criteria. I don't need (and don't want) to include ASP.Net Identity. In fact, I'm trying to avoid using as many of the things that MVC adds in as possible unless I really need them.</p>

<p>I've created a minimal project, which demonstrates the problem. To see the original code, just look through the edit history. I was expecting this sample to reject all requests for <code>/api/icons</code> unless they provide the <code>Authorization</code> HTTP header with a corresponding bearer token. The sample <strong><em>actually allows all requests</em></strong>.</p>

<p>Startup.cs</p>

<pre><code>using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Configuration;
using Microsoft.AspNetCore.Routing;
using Microsoft.IdentityModel.Tokens;
using System.Text;
using System;
using Newtonsoft.Json.Serialization;

namespace JWTSecurity
{
    public class Startup
    {
        public IConfigurationRoot Configuration { get; set; }

        public Startup(IHostingEnvironment env)
        {
            IConfigurationBuilder builder = new ConfigurationBuilder().SetBasePath(env.ContentRootPath);
            Configuration = builder.Build();
        }

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddOptions();
            services.AddAuthentication();
            services.AddMvcCore().AddJsonFormatters(options =&gt; options.ContractResolver = new CamelCasePropertyNamesContractResolver());
        }

        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
            loggerFactory.AddConsole();
            app.UseJwtBearerAuthentication(new JwtBearerOptions
            {
                AutomaticAuthenticate = true,
                AutomaticChallenge = true,
                TokenValidationParameters = new TokenValidationParameters
                {
                    ValidateIssuerSigningKey = true,
                    IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes("supersecretkey")),
                    ValidateIssuer = false,
                    ValidateAudience = false,
                    ValidateLifetime = true,
                    ClockSkew = TimeSpan.Zero
                }
            });
            app.UseMvc(routes =&gt; routes.MapRoute("default", "{controller=Home}/{action=Index}/{id?}"));
        }
    }
}
</code></pre>

<p>Controllers/IconsController.cs</p>

<pre><code>using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

namespace JWTSecurity.Controllers
{
    [Route("api/[controller]")]
    public class IconsController : Controller
    {
        [Authorize]
        public IActionResult Get()
        {
            return Ok("Some content");
        }
    }
}
</code></pre>