The bad rabbit ransomware disguises itself into an Adobe Flash installer. If you install it, you'll get infected.
So, as long as you stay away from suspicious looking links, ads, emails, etc. You should be fine. Try to avoid freeware programs as much as you can too.
Using a security program would be a plus. But, common sense should be enough. I've only been using Windows Defender as my Antivirus and MalwareFox as my Anti-Malware for months now. Stay safe mate.