Information
Auto Update verifies that your system has the newest security patches and software updates. If 'Automatically check for updates' is not selected, background updates for new malware definition files from Apple for XProtect and Gatekeeper will not occur.
http://macops.ca/os-x-admins-your-clients-are-not-getting-background-security-updates/
https://derflounder.wordpress.com/2014/12/17/forcing-xprotect-blacklist-updates-on-mavericks-and-yosemite/
Rationale:
It is important that a system has the newest updates applied so as to prevent unauthorized persons from exploiting identified vulnerabilities.
Impact:
Without automatic update, updates may not be made in a timely manner and the system will be exposed to additional risk.
Solution
Graphical Method:
Perform the following steps to enable the system to automatically check for updates:
Open System Preferences
Select Software Update
Select Advanced
Set Check for updates to enabled
Terminal Method:
Run the following command to enable auto update:
$ /usr/bin/sudo /usr/bin/defaults write /Library/Preferences/com.apple.SoftwareUpdate AutomaticCheckEnabled -bool true
Profile Method:
Create or edit a configuration profile with the following information:
The PayloadType string is com.apple.SoftwareUpdate
The key to include is AutomaticCheckEnabled
The key must be set to <true/>