BadBotBlocker 1.0.1

BadBotBlocker 🛡️

Welcome to the BadBotBlocker ASP.NET Core middleware! This library provides an efficient and customizable way to block malicious bots, scrapers, and unwanted traffic based on User-Agent patterns and IP ranges. It leverages a popular list of rules from an .htaccess file and focuses on extreme performance using the latest C# features.

Overview

The BadBotBlocker middleware offers:

• Default Blocking Rules: Preloaded with a comprehensive list of bad bot User-Agent patterns and IP ranges.
• Customizable: Easily add or remove patterns and IP ranges to suit your application's needs.
• High Performance: Optimized pattern matching and minimal overhead.
• Extensibility: Provides extension methods for dependency injection and middleware configuration.

Getting Started

Installation

You can install the BadBotBlocker package from NuGet:

dotnet add package BadBotBlocker

Setting Up Dependency Injection

To use the BadBotBlocker middleware in your ASP.NET Core application, configure your services in Program.cs or Startup.cs.

Using Default Blocking Rules

public void ConfigureServices(IServiceCollection services)
{
    services.AddBadBotBlocker();

    // Other service configurations...
}

Customizing Blocking Rules

public void ConfigureServices(IServiceCollection services)
{
    services.AddBadBotBlocker(options =>
    {
        options.ClearBadBotPatterns();
        options.ClearBlockedIPRanges();

        options.AddBadBotPattern("^MyCustomBot")
               .AddBlockedIPRange("192.168.1.0/24");
    });

    // Other service configurations...
}

Usage

In your Program.cs or Startup.cs, add the middleware to the HTTP request pipeline:

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.UseBadBotBlocker();

    // Other middleware...
    app.UseRouting();
    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllers();
    });
}

How It Works

The BadBotBlocker middleware intercepts incoming HTTP requests and performs the following checks:

1. IP Address Check: Determines if the client's IP address falls within any of the blocked IP ranges.
2. User-Agent Check: Matches the client's User-Agent string against a list of known bad bot patterns.

If a match is found in either check, the middleware responds with a 403 Forbidden status code, effectively blocking the request.

Default Blocking Rules

The middleware comes preloaded with a comprehensive list of bad bot User-Agent patterns and IP ranges, extracted from a popular .htaccess file. These include:

• Bad Bot User-Agent Patterns: Over 200 patterns matching known malicious bots and scrapers.
• Blocked IP Ranges: Specific IP ranges associated with unwanted traffic.

Examples of Default User-Agent Patterns

• ^Aboundex
• ^80legs
• Baiduspider (Aggressive Chinese Search Engine)
• Yandex (Aggressive Russian Search Engine)
• Acunetix (Vulnerability Scanner)

Examples of Default Blocked IP Ranges

• 38.100.19.8/29
• 65.213.208.128/27
• IP ranges associated with Cyveillance and other entities.

Extensibility

You can customize the blocking rules by adding or removing patterns and IP ranges:

services.AddBadBotBlocker(options =>
{
    // Remove all default patterns and IP ranges
    options.ClearBadBotPatterns();
    options.ClearBlockedIPRanges();

    // Add custom patterns
    options.AddBadBotPattern("^CustomBot")
           .AddBadBotPattern("BadScraper");

    // Add custom IP ranges
    options.AddBlockedIPRange("123.456.789.0/24");
});

Supported Classes and Methods

BadBotOptions Class

BadBotMiddlewareExtensions Class

Performance Considerations

• Optimized Pattern Matching: Differentiates between simple StartsWith patterns and complex regex patterns to minimize overhead.
• Compiled Regular Expressions: Uses RegexOptions.Compiled for regex patterns to improve matching performance.
• Efficient IP Address Checking: Utilizes an extension method for IPAddress to check IP ranges without external libraries.

Example

Blocking Custom Bots and IP Ranges

services.AddBadBotBlocker(options =>
{
    options.AddBadBotPattern("^SneakyBot")
           .AddBadBotPattern("EvilScraper")
           .AddBlockedIPRange("10.0.0.0/8")
           .AddBlockedIPRange("172.16.0.0/12");
});

Middleware Configuration

app.UseBadBotBlocker();

Requirements

• .NET 8.0 or higher: The library utilizes the latest features of C# 12 and .NET 8.
• ASP.NET Core Application: Designed to work with ASP.NET Core middleware pipeline.

License

This library is available under the MIT License.

Contributions

Pull requests and contributions are welcome! Please open an issue to discuss any changes before submitting a pull request.

About

For more information or support, please visit the GitHub Repository.

Thank you for using BadBotBlocker. We look forward to your contributions and feedback!