using netcat effectively

netcat.txt

Netcat is a great tool to use to listen and forward ports as a simple proxy or routing of data.

Example:

Usb device connected and running on /dev/bus/usb/002/009 (revealed from lsusb -v command).

To get data from the device:

cat /dev/bus/usb/002/009/ 


root@ubuntu-linux-20-04-desktop:/home/parallels# cat /dev/bus/usb/002/009 | hexdump
0000000 0112 0110 0000 0800 072f 2200 0216 0201
0000010 0100 0209 005d 0101 8000 09c8 0004 0300
0000020 000b 0000 2136 0100 0700 0002 0000 0fa0
0000030 0000 0fa0 0000 0000 002a 9000 03d0 0000
0000040 0100 0000 0000 0000 0000 0000 0040 0002
0000050 010f 0000 0000 0000 0100 0507 0381 0008
0000060 0732 0205 4002 0100 0507 0282 0040 0001
000006f

To use netcat to pipe that data to a local port:


root@ubuntu-linux-20-04-desktop:/home/parallels# cat /dev/bus/usb/002/009 \
 | hexdump | nc -l localhost 8181
In another terminal window, get the data (or from code you write to get it programmatically streaming in:


parallels@ubuntu-linux-20-04-desktop:~$ nc localhost 8181
0000000 0112 0110 0000 0800 072f 2200 0216 0201
0000010 0100 0209 005d 0101 8000 09c8 0004 0300
0000020 000b 0000 2136 0100 0700 0002 0000 0fa0
0000030 0000 0fa0 0000 0000 002a 9000 03d0 0000
0000040 0100 0000 0000 0000 0000 0000 0040 0002
0000050 010f 0000 0000 0000 0100 0507 0381 0008
0000060 0732 0205 4002 0100 0507 0282 0040 0001
000006f

As you can see, this is a powerful way to listen and get device data streaming in to evaluate anything plugged in virtually or physically to systems.