How do you disable directory listing in Amazon Cloudfront?
Did you already get it? If not, you can try setting Default Root object for your cloudfront distribution.
setting Default Root should work. Another option is to just put any index.html file at your root. You could take a blank text file and rename it "index.html", or put some generic HTML message in the file too. Either way, a call to root of your cloudfront distribution will just default to that file instead of listing your directories / files.