malicious attack on iphone calendar

hello Guys,

Today I searched iPhone wallpaper on google through safari browser, I found one site where I downloaded one image but after that I got unknown error whereas there is no back option I must clicked on the done option to further proceed. Hence I clicked on that and afterwards I got an unexpected message showing “malicious attack on iphone calendar” I don’t know what to do! My iPhone is not in warranty anymore so can’t get official help from iPhone.

can anyone help me out with this!

thanks.