How to use Telnet

Most of you only know that TelNet is a Port ( Port 23 ) or that TelNet is a Remote Control Tool. Remote Control means in this aspect that you as Client can get a Connection to for example a TelNet Server and then you can write Commands in a derivative of a Shell and this commands are executed only on this server not on your machine. But I want to show all you guys how to use this simple Remote Control Tool in several ways, because this simpleness is brilliant. 

How to use TelNet

TelNet is a text based tool. So if you want to connect to the destination (128.62.254.12) write: ‘telnet 128.62.254.12 23’.So you see at first there is the command telnet to start the TelNet Client, the next is the destination address and last is the Port,you know the TelNet port 23. So I hope now you can use TelNet.

How to send Anonymous Mails

SMTP

Yes first I have to say something about the SMTP ( Simple Mail Transfer Protocol ). The standard is written down in the RFC 821( RFC = Request for Comments ) it goes back to the year 1982. This RFC defines the commands which could be used.

This Commands are:
1. HELO <Client Adress or Name> – It marks the begin of that TelNet session and sends your name or address to the SMTP Server

2. MAIL FROM:<your mail addie> – with this command you send your mail addie to server which is also written in the e-mail as sender

3. RCPT TO:<recipient> – with this command you define the recipient

4. DATA – this marks the begnning of the e-mail if the server sends an ack ( ackwoledge ) you can begin to write the message   if you have ended you have to mark it with an command or character which was sent to you after you have sent the command DATA5. RSET – =Reset this establishs the initial stage and the connection is canceled

6. NOOP – =No Operation so it means that nothing is done

7. QUIT – This is the ending of the SMTP connection
But this are only the most important commands many commands have been added in this time after the RFC has defined them. For example EXPN – =expand with this command maillist support will be availableVRFY – =verify this command requests the confirmation of the recipient addressCaused of this addition the SMTP is also called ESMTP which means Extended SMTP. So I hope you have learned something in this section.

How to use SMTP to send anonymous mails

First you have to find a free accessable SMTP server. Caused by Spaming many servers has secured their systems like GMX with ‘SMTP afterPOP’ which means that at first you have to login at POP with your username and password for your GMX e-mail addie. After that the Server saves your IP for a special time in which you can connect to SMTP server to send mails. Freenet uses another secured system. This SMTP server denies special recipient addies. So you have to search a free accessible Mail server with out such secured servers. They exists.So after you have found such a server you can write in your shell: ‘telnet <serveraddy> 25’ then your client connects to it.Here is a complete TelNet

Session:
Connected to mail.gmx.net.220 {mp015-rz3} GMX Mailservices ESMTPHELO http://www.The-Netrix.net250 {mp015-rz3} GMX Mailservices

MAIL FROM:LinusTorvalds@linux.org250  … Sender Okay RCPT TO:BillGates@microsoft.com250  … Recipient Okay DATA354

Enter mail, end with “.” on a line by itself

250 Mail acceptedQUIT221 mail.gmx.net closing connection

Connection closed by foreign host.

I will help you to understand this. First your Client tries to connect to the mail server. As sign that the connection is established the server answers with a command like that. Then you say hello to the server with the command ‘HELO’ and your machines name. Next is another answer from server which is unimportant.

After it you send your mail addy to server with the command ‘MAIL FROM:’ followed by your addy. Then the server check this addy and if it’s OK he will inform you about it. Next he expects the recipient and you won’t let him wait with the command ‘RCPT TO:’ followed by the addy of the recipient. If it’s also OK you can start to write your mail after the command ‘DATA’ which is followed by the ack of the server and the text or character which marks the end of the mail.Then you write your mailand end it how the server expect it. If the mail is OK the server will inform you for the last time in this session. After it there is no cause which should hold your connection so you will end it with ‘QUIT’ and the server will send a last stupid message as sign that the connection is closed.This was only a stupid example to show you how you can send mails with TelNet.

How to use TelNet in several aspects

How to delete files off a Website

There is a way to delete files of a website with the help of the HTTP ( Hyper Text Transfer Protocol ). But this security hole is mostely closed. This hole is caused by stupid administrators which can’t configure there Apache or IIS or any other HTTP server.

The HTTP exists since 1990. Before this time the internet was used to make a file exchange with the FTP or to get in Mailboxes where you can write messages or many other things. With the HTTP and HTML ( Hyper Text Mark Language ) the www-Clients like Netscape or IE can interpret this Hyper Text to display information or other things like you know. But what the user can’t see when he uses such a client that the HTTP follows also the Request-Answer-play. The client requests information with a special command, which i will explain beside others later, and the HTTP server answers with the requested information. This requests or answers are HTTP messages which could be simple-request or simple-response or full-request or full-response. The simple HTTP-messages based on HTTP/0.9 and the full messages on HTTP/1.0 . But the difference between this messages is very small, except the one of HTML/0.9 and HTML/1.0.

The commands:
1. GET <address> – the address is the whole like http://www.destination.com/index.html this command requests the informations ( the code )    in this file and if  the file is a CGI it have to be executed and the produced informations will be send to client                 – the difference between this simple-request and the full request is that the full-request ends with HTTP/1.0    like this: ‘GET http://www.destination.com/index.html HTTP/1.0’2. HEAD <addy> – it have to be a complete addy, too. The small difference between this command and the GET command is that this command only META-Tags and the other informations in the title tag3. POST <addy> – this is used for bigger data it is mostley used for data which have to be send to a program4. PUT <addy> – with put you send data to the server like HTML documents and this data is saved under the addy which you have declared5. DELETE <addy> – this is the opposite of PUT so it deletes the data which you have specified with the addy

How to delete files of a Website

So with your instinct you have discovered that there is a security hole. The HTTP protocol today is used in combination with the FTP, so that means FTP is used by webmasters to upload their files and HTTP is used by the Client to resolve these site. But in former times concrete: at the development of the HTTP the developers aimed to make it easier to upload files, so not with the FTP and that means without special FTP-Client, so they created a command to upload and delete files on a webserver. But the problem is that the HTTP didn’t use an authentication but FTP does. So that means that the most administrators disabled these Commands to shut a security hole. But there are not only experienced admins out there but stupid, too. So there is still such a hole which waits to be used. How ever TelNet is an excellent simple tool. So if you want to use this security hole connect to the destination hostname or IP (you can use a hostname because DNS will be used to resolve the IP) on Port 80. I’ve showed you guys how to do it. So do it. When the connection is established you can use the commands which are described in section

Example to delete the index.html: DELETE http://www.microshit.com/index.html

So I hope you will enjoy using TelNet not only in this way, you can use it also if you want to open a RAW-IRC-Session. USE YOUR BRAIN!

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.