Janda.CTF

Capture The Flag is a console application challenge runner.

Visual Studio Quick Start

1. Create QuickStart Console App (.NET Core).
2. Add Janda.CTF nuget package.
3. Add CTF.Run to Program.cs.

Program.cs

using Janda.CTF;

namespace QuickStart
{
    class Program
    {
        static void Main(string[] args) => CTF.Run(args);
    }
}

4. Run program with Add profile to create C001 challenge

launchSettings.json

CTF nuget package provides Help and Add profiles

{
  "profiles": {
    "Add": {
      "commandName": "Project",
      "commandLineArgs": "add --name C001"
    },
    "Help": {
      "commandName": "Project",
      "commandLineArgs": "--help"
    }
  }
}

5. Implement Run for C001 challenge.

C001.cs

The challenge class was added by CTF challenge runner.

using Microsoft.Extensions.Logging;

namespace Janda.CTF
{  
    public class C001 : IChallenge
    {
        private readonly ILogger<C001> _logger;

        public C001(ILogger<C001> logger)
        {
            _logger = logger;
        }
        
        public void Run()
        {
            _logger.LogInformation("I will capture the flag!");
        }
    }
}

6. Run the challenge with C001 profile

launchSettings.json

C001 profile was added by CTF runner

{
  "profiles": {
    "Add": {
      "commandName": "Project",
      "commandLineArgs": "add --name C001"
    },
    "Help": {
      "commandName": "Project",
      "commandLineArgs": "--help"
    },
    "C001": {
      "commandName": "Project",
      "commandLineArgs": "--name C001"
    }
  }
}

Output

[22:24:33 VRB] Using CTF runner 1.0.0
[22:24:33 VRB] Running challange C001
[22:24:33 INF] I will get the flag!
[22:24:33 VRB] Challenge C001 completed

7. Create your services. For example FlagFinder service.

IFlagFinder.cs

namespace QuickStart
{
    public interface IFlagFinder
    {
        void FindFlag();
    }
}

FlagFinder.cs

using Microsoft.Extensions.Logging;

namespace QuickStart
{
    public class FlagFinder : IFlagFinder
    {
        readonly ILogger<FlagFinder> _logger;

        public FlagFinder(ILogger<FlagFinder> logger)
        {
            _logger = logger;
        }

        public void FindFlag()
        {
            _logger.LogInformation("Looking for a flag...");
        }
    }
}

8. Add your service to CTF runner

Program.cs

using Janda.CTF;
using Microsoft.Extensions.DependencyInjection;

namespace QuickStart
{
    class Program
    {
        static void Main(string[] args) => CTF.Run(args, (services) =>
        {
            services.AddTransient<IFlagFinder, FlagFinder>();
        });
    }
}

9. Add your service to the challenge service

C001.cs

using Microsoft.Extensions.Logging;
using QuickStart;

namespace Janda.CTF
{  
    public class C001 : IChallenge
    {
        readonly ILogger<C001> _logger;
        readonly IFlagFinder _flagFinder;

        public C001(ILogger<C001> logger, IFlagFinder flagFinder)
        {
            _logger = logger;
            _flagFinder = flagFinder;
        }

        public void Run()
        {
            _logger.LogInformation("I will capture the flag!");
            _flagFinder.FindFlag();
        }
    }
}

10. Run C001 challenge with IFlagFinder service

Output

[23:01:20 VRB] Using CTF runner 1.0.0
[23:01:20 VRB] Running challange C001
[23:01:20 INF] I will capture the flag!
[23:01:20 INF] Looking for a flag...
[23:01:20 VRB] Challenge C001 completed