I found ettercap a long time ago and I will be honest in saying that once or twice since then, I’ve put it to work.
I say that with a small measure of guilt — because, while it’s a very flexible tool and quite useful for some minor troubleshooting tasks, it’s main focus is something a little more devious.
And that’s the part where I promise, I know nothing. I said a long time ago, and it bears repetition: ettercap is a tool, in the same way a knife is a tool or a hammer is a tool.
You could do good things with a knife or hammer, but you could also wreak havoc. And you could list a lot of other things alongside a knife or a hammer, some of them quite mundane.
I leave it to you, what you do with ettercap. The potential is there to do good … or evil. 👿
P.S.: There’s a GTK version too.