It's fake. They're trying to get you to pay a scam company.
If the computer has 10.10.4 on it, the user will eventually get the option to stop showing further dialogs from that site, in case it keeps popping up.
If it pops up once ignore it, it's fake and not from Apple. If it pops up often and on multiple sites then it would be a good idea to scan with a program like Adware Medic.
If the computer has 10.10.4 on it, the user will eventually get the option to stop showing further dialogs from that site, in case it keeps popping up.
I've had the same thing happen with my Macbookpro, OS X 10.7.5, with this alert
Are you sure you want to leave this page?
MAC iOS Alert
This security update provides a fix for SSL connection verification. For information on the security content of this update and to unlock the MAC iOS please visit www.support.apple.com Or call 1-844-685-4476.
Call for immediate Assistance 1-844-685-4476
It has locked the page...I can force quit Safari, but when I reopen the page this Alert is still there..I tried restarting and turning computer off then back on but it's still there...
Any suggestions greatly appreciated.