TrafficFilter 0.1.0-alpha

TrafficFilter

ASP.NET Core middleware for request filtering and rate limiting

About

TrafficFilter is an ASP.NET Core middleware that enables request filtering and rate-limiting. There are the following request filtering features:

• Url filtering
• Headers filtering
• Rate limiting

Each feature can be enabled and configured in the config file.

TrafficFilter may be useful in scenarios when you want to protect your web app and server resources from various scanning bots that try to access non-existent URLs by blacklisting their IP addresses for a configured amount of time.

Another use case could be protecting the app if it is accessed using a public server IP address.

It can also block traffic if configured path-based rate limit is reached.

Getting Started

First install the TrafficFilter NuGet package using PowerShell:

PM> Install-Package TrafficFilter

or via the dotnet command line:

dotnet add package TrafficFilter

Then add the TrafficFilter middleware to your ASP.NET Core Startup class:

using TrafficFilter;

namespace SampleWebApp
{
    public class Startup
    {
        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            // --- TrafficFilter ---
            services.AddTrafficFilter(Configuration);

            //...
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            // --- TrafficFilter - topmost important! ---
            app.UseTrafficFilter();

            //...
        }
    }
}

Add TrafficFilter configuration section to appsettings.json, modify it as needed:

"TrafficFilter": {
    "IPBlacklistTimeoutSeconds": 5,
    "RequestFilterUrl": {
      "IsEnabled": true,
      "Matches": [
        {
          "Type": "MatchRegex",
          "Match": "https?:\\/\\/[\\d*\\.*]+" //Pattern for IP Address based Url
        },
        {
          "Type": "MatchEndsWith",
          "Match": ".xml"
        },       
        {
          "Type": "MatchContains",
          "Match": "mysql"
        },
        {
          "Type": "MatchStartsWith",
          "Match": "ftp"
        }
      ]
    },
    "RequestFilterHeaders": {
      "IsEnabled": true,
      "Matches": [
        {
          "Header": "user-agent",
          "Type": "MatchContains",
          "Match": "x-bot"
        }
      ]
    },
    "RateLimiter": {
      "IsEnabled": true,
      "RateLimiterWindowSeconds": 1,
      "RateLimiterRequestLimit": 10,
      "SkipUrls": [ // Add matches here if you want to exclude them from rate limiting
        {
          "Type": "MatchEndsWith",
          "Match": ".mp4"
        }
      ]
    }
  }

Documentation

If any of the enabled filters matches the incoming request, the requester's IP address is added to the blacklist for the duration of IPBlacklistTimeoutSeconds and HttpStatusCode.TooManyRequests is returned.

Possible values for Match Type are: MatchStartsWith, MatchContains, MatchEndsWith and MatchRegex.

License

Apache 2.0