Automatic Security Updates For Your Macintosh

Your Macintosh has several built-in security features, including anti-virus software and the ability to disable compromised infection vectors.
http://en.wikipedia.org/wiki/Xprotect
https://support.apple.com/en-us/HT201940
This article tells you how to keep these features updated, automatically:

Ensuring your Mac is receiving updates about new malware and compromised web plug-ins
http://www.idownloadblog.com/2016/05/10/tip-enable-file-quarantine-updates/

The most important part of the above article is to do this:

System Preferences --> App Store --> ensure that the box next to “Install system data files and security updates” is ticked

Thanks for the update Randy.

Just by way of clarification that setting is not the same as the one about installing system updates.