I think I'll abandon this discussion. meanwhile, in my opinion you don't know as much as you think you know about this. That it should be difficult to turn off a firewall is simply not true. At some point a user will end up installing a program with root (admin) access, simply because that particular application (whatever it says it's supposed to do) will have to be installed that way. For Windows, for example, there's almost nothing that installs without admin rights. From there on it's simple - you (the trojan) can do whatever you want.

But this is what I've been repeating, so I'll stop the repeat cycle there. Disagree if you want, I've said my piece.