Weird User in my login screen "puppet"

As per puppet doc for mac installation:

The puppet master service needs a puppet user and group.

So you can be sure now that you haven't been hacked :)


FYI, you can hide this user from the login screen:

sudo dscl . create /Users/puppet IsHidden 1 

Or in pre-Yosemite versions:

defaults write  /Library/Preferences/com.apple.loginwindow HiddenUsersList -array-add puppet

Source