Ubuntu security question?

viruses are not a issue on linux.there are none in the wild currently .the only way to trash ubuntu currently is to surf as root then download a malicious .deb file and then agree to infect yourself.of course its possible simply because as secure as ubuntu default settings are if one is stupid then watch out.i don't like computer janitor.bleachbit is much better.ubuntu has no registry so i use bleachbit to clear the cache and wipe out history and cookies.another bad habit on ubuntu is allowing remote log in.just inviting a hack job.use strong passwords and change them once in awhile.if your not behind a good router then enable ufw firewall.