Comment 39 for bug 364917

ok try this in your bash:

sudo mkdir ettercap
cd ettercap
wget https://launchpad.net/~timothy-redaelli/+archive/drizzt/+files/ettercap-common_0.7.3-1.4ubuntu1drizzt1_i386.deb
wget https://launchpad.net/~timothy-redaelli/+archive/drizzt/+files/ettercap-gtk_0.7.3-1.4ubuntu1drizzt1_i386.deb
wget https://launchpad.net/~timothy-redaelli/+archive/drizzt/+files/ettercap_0.7.3-1.4ubuntu1drizzt1_i386.deb
sudo dpkg -i *.deb
cd ..
sudo rm ettercap -Rf

for creating the directory ettercap
go into the directory
wget stands for downloading a file from internet
(you have to download the three files in order to make it work)
dpkg -i is useful to manually install a package and *.deb stands for install every deb files in this directory)
rm stands for remove directory ettercap