NETBIOS BASED HACKING TUTORIAL   BY GAURAV KUMAR


Note- This tutorial may bear a resemblance to tutorials written by other authors. I have acknowledged  to tutorials or articles  that I referred  before writing this tutorial.  It is possible that there may be other tutorials I have not referred and are similar to my tutorial. It is not possible for me to give acknowledgment to such tutorials and hence there must be no copyright or legal issues regarding this tutorial.


Dear reader I have written this tutorial keeping in mind that readers having only the basic knowledge will also be able to know how hackers hack using NetBIOS. Using NetBIOS for hacking is the probably the easiest way to hack remotely. I strongly  oppose hacking but not ethical hacking. An ethical hacker is one that hacks computer networks not for anti social reasons but to let the network administrators know about the security holes so that they can prevent their computers from hacking. If you want to contact me please send me a mail to


A brief  lesson on NetBIOS

The NBTSTAT command

What you need to hack ?

Types of attacks

Searching for a victim

Lets Hack - Part 1 Remotely reading/writing to a victim's computer

Cracking  "Share "passwords

Using IPC$ to hack Windows NT

Penetrating in to the victim's computer

Lets Hack - Part 2 Denial of service attack

How to protect yourself


                                              A BRIEF LESSON ON NETBIOS

NetBIOS stands for Network Basic Input Output System  .It was originally developed by IBM and Sytek as an Application Programming Interface (API) for client software to access LAN resources. If you have experience of working on a LAN using Microsoft Windows Operating Systems (like Windows98 , Windows Me, Windows NT etc), you must have clicked on "Network Neighborhood" to access the computers attached to your network. After clicking on the icon you would have seen the names of the computer . Do you know what exactly happens when you click on Network Neighborhood? Your computer tries to get the names of the computers attached to the network with by issuing command to NetBIOS . NetBIOS gives the name of the computers that have been registered . In short NetBIOS gives the various information of the computers on a network . These Include-

Name of the computer



Computer Name

and many others.

Like any other service it also works on a port . It  has been assigned a port number 139.



                                                  THE NBTSTAT COMMAND

You can manually interact with the NetBIOS with the help of NBTSTAT command. To use this command click on the start button then select RUN... and type "command" without quotes to launch MS-DOS Command Prompt. Alternatively you may click on Start Button then go to Programs and then select Command Prompt. Once you are in Command Prompt you can exit by typing command EXIT . To launch Command Prompt in full screen mode press ALT+ENTER key combination .To get back to the original window again press ALT+ENTER key combination. If you have launched the command prompt you will get


If you do not get windows displayed after c:\ don't worry just keep going , all required commands will work fine.

Now lets play with the NBTSTAT command.

If you want to get more help from MS-DOS about this command type NBTSTAT/? on the prompt i.e.


If you want to get the NetBIOS information of your computer type the following command

c:\windows>nbtstat -a

This command will list the NetBIOS information. A typical  example

                                    NetBIOS Remote Machine Name Table

Name                            Number             Type                 Usage


workgroup                      00                     G                      Domain Name

my_computer                 03                     U                      Messenger Service

myusername                  03                     U                      Messenger Service

MAC Address = 00-02-44-14-23-E6


Please note that we have used our ip address to be . This ip address is called as "Loop Back" ip address because this ip address always refers to the computer you are using.

This example is self explanatory . We need not go in details. We need to know about the Name and Number. The Name displays the Name of the NetBIOS and there is a corresponding hexagonal number . You may see some additional names in your case.

If you want to get the NetBIOS names of a remote computer, the command is

c:\windows>nbtstat -a ipaddress

Example - To get the NetBIOS names of a computer having ip address, we shall use the command

NOTE- may be a active ip address of someone's computer. I am using it only as an example. Please don't hack this computer.

c:\windows>nbtstat -a

If you want to get to know more about  the ip address and ports click here



                                             WHAT YOU NEED TO HACK

All you need is a Windows based operating system like Windows 98 and Me (but I prefer Windows NT, 2000, XP) and an internet connection.




                                           TYPES OF ATTACKS

We can launch two types of attack on the remote computer having  NetBIOS.

1. Reading/Writing to a remote computer system

2. Denial of Service



                                                      Searching for a victim

You may manually search for the victims by first using the nbtstat -a ipaddress and then net view \\ipaddress . If at first you don't succeed step to next ip address until you find a suitable ip address. You may also use a port scanner .A port scanner is simply a software that can search for any block of ip address say to for one or more ports.  "Orge" is a port scanner that  gives NetBIOS names of the remote computer.



                 Lets Hack -Part 1 Remotely reading/writing to a victim's computer

Believe it or not but NetBIOS is the easiest method to break into somebody's computer. However there is a condition that must be satisfied before you can hack. The condition is that the victim must have enabled File And Printer Sharing on his computer. If the victim has enabled it , the nbtstat command will display one more NetBIOS name. Now lets us take a example. Suppose you know a ip address that has enabled File And Printer Sharing and let suppose the ip address happens to be .

If you would like to know more about  ip address click here . If you don't the ip address where File and Printer  Sharing is enabled read "Searching for a victim"

The command that you will use to view the NetBIOS name is

c:\windows>nbtstat -a

Let suppose that the output comes out to be

         NetBIOS Remote Machine Name Table

Name                        Type             Status
user            <00>     UNIQUE       Registered
workgroup  <00>    GROUP        Registered
user            <03>     UNIQUE       Registered
user            <20>     UNIQUE       Registered

MAC Address = 00-02-44-14-23-E6


The number <20> shows that the victim has enabled the File And Printer Sharing.


NOTE - If you do not get this number there are two possibilities

1.  You do not get the number <20> . This shows that the victim has not enabled the File And Printer Sharing .

2.  You get "Host Not found" . This shows that the port 139 is closed or the ip address doesn't exists.


Now our next step would be to view the drive or folders  the victim is sharing.

We will use command

c:\windows>net view \\

Let suppose we get the following output

Shared resources at \\

Share  name                Type           Used as           Comment

CDISK                            Disk

The command completed successfully.


 "DISK" shows that the victim is sharing a Disk named as CDISK . You may also get some additional information like


Shared resources at \\

 Share  name                Type           Used as           Comment
HP-6L                             Print


"Print " shows that the victim is sharing a printer named as HP-6L

 If we are able to share the victims hard disks or folders or printers we will be able to read write to the folders or hard disks or we may also be able to print anything on a remote printer ! Now let us share the victims computer's hard disk or printer.

Till now we know that there is a computer whose ip address happens to be and on that computer File and printer sharing is enabled and the victim's hard disk 's name is CDISK.

Now we will connect our computer to that hard disk . After we have connected successfully a drive will be created on our computer and on double clicking on it we will be able to view the contents of the drive. If we have connected our newly formed drive to the victim's share name CDISK it means that we our drive will have the same contents as that of the CDISK .

Lets do it.

We will use the NET command to do our work .

Let suppose we want to make a drive k: on our computer and connect it to victim's share we will issue the command

c:\windows>net use k: \\\CDISK

You may replace k letter by any other letter.

If the command is successful we will get the confirmation - The command was completed successfullly

The command was completed successfully

Now just double click on the My Computer icon on your desktop and you will be a happy hacker!

We have just crested a new drive k: . Just double click on it and you will find that you are able to access the remote computer's hard disk. Enjoy your first hack!



                                                      Cracking  Share passwords

Sometimes when we use "net use k: \\ipaddress\sharename" we are asked for a password. There is a password cracker "PQWAK" . All you have to enter ip address and the share name and it will decrypt the password within seconds. Please note that this can crack only the passwords is the remote operating system is running on -

Windows 95

Windows 98

Windows Me



                                              Using IPC$ to hack Windows NT

Now you must be thinking of something that can crack share passwords on  NT based operating systems like Windows NT and Windows 2000.

IPC$ is there to help us. It is not at all a password cracker . It is simply a string that tells the remote operating system to give guest access that is give access without asking for password.

We hackers use IPC$ in this way

c:\windows>net use k:  \\\ipc$ "" /user:""

You may replace k letter by any other letter. If you replace it by "b" (type without quotes) a new drive will be created by a drive letter b.

Please note that you won't be able to get access to victim's shared drives but you you can gather valuable information like names of all the usernames, users that have never logged, and other such information. One such tool that uses the ipc$ method is "Internet Periscope"



                                        Penetrating in to the victim's computer

Now that you have access to a remote computer you may be interested in viewing  his secret emails, download his mp3 songs , and more...

But if you think like  a hard core hacker you would like to play some dirty tricks like you may wish to install a key logger or  install a back door entry Trojan like netbus and backorifice or delete or copy some files. All these tasks involves writing to victim's hard disk . For this you need to have write access  permission and this can only be granted by the remote user .



                                         Lets Hack - Part 2 Denial of service attack


This type of attacks are meant to be launched by some computer techies because this type of attack involves using Linux Operating System and compiling C language files .

The two most common vulnerabilities found in NetBIOS are

Vulnerability 1

Vulnerability 2



                                                  How to protect yourself

Please visit and let the windows update itself.


The above tutorial has been written by Gaurav Kumar

If you need more help please feel free to email me


                                                             END OF TUTORIAL

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Other tutorials by Gaurav Kumar

                                     ALL ABOUT NETSTAT

                                     ALL ABOUT IP ADDRESSES

More tutorials coming soon...