As reported by Apple Support, and mentioned by Apple Insider and 9to5Mac news sites, Apple just released a firmware update for Mac Mini hardware for some models.
“This update is recommended for Mac mini (late 2012) models. This update addresses an issue that may prevent a USB keyboard from being recognized after the system wakes from sleep.”
I don’t know specifics of this release, and what security implications this has.
More Information:
https://support.apple.com/en-us/HT201518
https://support.apple.com/kb/DL1828?locale=en_US
http://appleinsider.com/articles/15/07/15/apple-releases-mac-mini-emi-firmware-update-to-fix-usb-keyboard-issue
Apple issues Mac mini EFI firmware update 1.8 to address USB keyboard problem
Firmware Security 