Ransomware doesn’t always have to trick you into installing something: It can sometimes spread on its own by exploiting security holes in legitimate software that hasn’t been properly updated or patched. This is one of the reasons you should generally install as few software programs on your computer as possible, and stick to developers that can be trusted to keep their applications secure and provide necessary security updates in a timely manner.
Besides being careful in terms of what you do on your computer and the programs you grant access, the standard three rules of system security apply: Update, protect, and back up. All malware, including ransomware, often exploits older or unpatched software, which is why it’s vital that everything running on your computer (and yes, that includes both Windows and macOS users) is up to date with at least the latest security updates.
Those nagging operating system updates are annoying for a reason—it’s really important that you get them installed. The good news is that software updates are so vital to security that they’re mostly handled automatically and in the background by most programs. Google Chrome, for example, downloads updates on its own, and you’ll see a color-coded icon in the toolbar when an upgrade is required. (It gets closer to red as the upgrade gets more urgent.)
In terms of protection, you also need some quality security software installed on your computer, but that should be done anyway—ransomware or no ransomware. It’s a matter of debate whether the tools built into Windows and macOS are good enough on their own, but they certainly go a long way to keeping malware threats, including ransomware, at bay.
It’s also fair to say that adding third-party software on top keeps you even better protected: Leading packages from the likes of McAfee, Norton, Bitdefender, Avira, and others will keep a very close eye on everything that’s happening on your system, so it’s up to you whether you think the extra protection is worth the extra cost (and the extra software configurations you’ll have to go through).