Well, i'm not exactly sure about them hiding anything as far as the article is concerned... They set up a litecoin mining botnet and out fear being detected -

Well, i'm not exactly sure about them hiding anything as far as the article is concerned... They set up a litecoin mining botnet and out fear being detected - and more generally doing the right thing - shut it down / reduced it to only a few bots.... So it's not like they actively tried to hide it via some kind of rootkit or the likes...