Search on the web if you want to find code that hides a program from task manager...

Also, Addons aren't loaded until you log into the game, and WoW Addons run in a restricted Lua engine that does not provide a method of accessing your login or password.

A week or two ago someone sent me an email saying they got hacked and they were certain it was because of my software (I didn't write AV enabler, but just as a related anecdote...). I explained to them that I've been in business since 2004 and it would be stupid -- and illegal -- for me to attempt to hack anyone's accounts when thousands of people rely on my software daily. I got an email back a few hours later with an apology, he checked his browser history and noticed that a link he clicked on in an email he got, sent him to one of the fake WoW scam sites (something related to cataclysm) and not the real one as it apparently looked like it would do.

I'm guessing something similar happened to you.