#пора_граммировать [6] ... авторизация на сайте МосБиржи #cookie

using System;
using System.Net;
using System.Text;

namespace AuthMoexSmpl
{
    class Program
    {
        static void Main(string[] args)
        { 
            string authLink = "https://passport.moex.com/authenticate";
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(authLink);
            request.ContentType = "text/plain; charset=utf-8";
            request.Headers["Authorization"] = "Basic " + Convert.ToBase64String(Encoding.GetEncoding("ISO-8859-1").GetBytes("login:password")); // вносим свои данные
            request.PreAuthenticate = true;
            request.CookieContainer = new CookieContainer();                 
            HttpWebResponse response = request.GetResponse() as HttpWebResponse;            
            foreach (Cookie cook in response.Cookies) {
                Console.WriteLine("Cookie:");
                Console.WriteLine("{0} = {1}", cook.Name, cook.Value);
                Console.WriteLine("Domain: {0}", cook.Domain);
                Console.WriteLine("Path: {0}", cook.Path);
                Console.WriteLine("Port: {0}", cook.Port);
                Console.WriteLine("Secure: {0}", cook.Secure);
                Console.WriteLine("When issued: {0}", cook.TimeStamp);
                Console.WriteLine("Expires: {0} (expired? {1})", cook.Expires, cook.Expired);
                Console.WriteLine("Don't save: {0}", cook.Discard);    
                Console.WriteLine("Comment: {0}", cook.Comment);
                Console.WriteLine("Uri for comments: {0}", cook.CommentUri);
                Console.WriteLine("Version: RFC {0}" , cook.Version == 1 ? "2109" : "2965");                
                Console.WriteLine ("String: {0}", cook.ToString());
            }                   
        }
    }
}

D:\devel\net\AuthMoexSmpl>dotnet run
Cookie:
_passport_session = xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Domain: passport.moex.com
Path: /
Port:
Secure: False
When issued: 11.11.2017 01:55:42
Expires: 01.01.0001 00:00:00 (expired? False)
Don't save: False
Comment:
Uri for comments:
Version: RFC 2965
...