Pretty common, especially in cider fermented at ale temps. It should age out.
If the sulphur aroma doesn't go away you can add a small piece of copper, like copper pipe, to the cider. Don't use pennies. They're mostly Zinc now, at least since ~1982. Cheers!!!
I've heard that and may give it a try with my perry. How long does it need contact?
That depends on how bad it is and how much copper is introduced. It might take up to a day or two. Your nose is the best test. You can suspend the copper in beer/wine/mead/cider with sanitized fishing line or in a sanitized nylon and move it around to get in into contact with as much beer/mead/wine/cider as possible. It's an amazing thing. I added a small section of copper tubing to the inside of my brew kettle as part of the dip tube and solved it. Cheers!!!