$ sudo apt-get update
$ sudo apt-get install ettercap-dbg 

ettercap-dbg is installed in your system.

Make ensure the ettercap-dbg package were installed using the commands given below,

$ sudo dpkg-query -l | grep ettercap-dbg *

You will get with ettercap-dbg package name, version, architecture and description in a table

ettercap-dbg package basic information: