Screenshare icon shows in login screen even though it is turned off
Login Window Picture
I tried clicking on it and nothing happens.
I did some researching on it and a Quora question popped up (https://www.quora.com/What-are-these-rectangles-icon-in-the-menu-bar-on-the-OS-X-El-Capitan-login-screen) about it, the answer said that
"Screen Sharing/BackToMyMac enabled and active. Someone is watching everything you're doing. If you did not turn that on, I would pull your network cable/turn your airport off"
I do not have Screen Sharing or Back To My Mac on, they are all disabled. How did it get turned on in the first place?
I turned off my wifi and the icon seemed to go away. Changed password, shut down my computer and came back to it. I just want to know how can I prevent this from happening in the future?
EDIT: Do the icons have further meaning or any other definitions? I did even more digging in the Quora link.
MacBook Pro Retina