It's a remote control tool rather than a trojan-as-such. It requires social engineering at least cos you have to get the target person to actually install the thing themselves. But yeah it's interesting that someone's making a commercial product like this to specifically target Linux with it being such a relatively tiny 'market'.
There are virtually no viruses for Linux because virtually no one uses it (on the desktop) :Y
But yeah, Linux is without a doubt more secure than Windows (vulnerabilities, when found, get patched very quickly and the underlying architecture just has a better security model). A file executed by a user would have a much harder time on Linux doing anything to the base system. But yeah it could quite easily trash/get access to anything your account has access to. i.e. all your online banking details :Y
And yeah, anything run with root privileges can do anything it likes. I run with passwordless sudo, for example, so you could trash my entire system with a one line bash script if you could get me to run it.
If you took all the people who currently run Windows and switched them to Linux overnight, a week later most of them would be infected with sommat, without a doubt.