Hackers have just defaced the index page of the site, which the message written,
"Just a security Reminder"At the mean time site still showing the deface page. As hackers points that, he had used a Zeroday exploit to hack the site.
You can check the hacked site (http://www.nic.sc/) and its mirror also at zone-h.
Remember, L33t hacker from the same group Madleets, who have hacked many of the high profiled sites and also the highest number of the .NIC domains last year.