Apple Inc's iCloud storage and backup service in China was attacked by hackers trying to steal user credentials, a Chinese web monitoring group said, adding that it believes the country's government is behind the campaign. Using a method called a "man-in-the-middle" attack, unknown hackers interposed their own website between users and Apple's iCloud server, intercepting data and potentially gaining access to passwords, iMessages, photos and contacts, Greatfire.org wrote in its blog post.