If you’re using Apple’s latest desktop OS, Yosemite, you might want to adjust your iCloud settings to avoid unsaved documents ending up on Apple’s servers.
Apple’s latest desktop OS, OS X Yosemite, and its latest mobile update, iOS 8.1 are designed to make work across multiple Apple devices a lot more convenient, courtesy of syncing features rooted in iCloud Drive (Apple’s answer to Dropbox) and “continuity”.
Continuity and its companion “Handoff” allow users to start writing an email on an iOS 8 device and “pick up where you left off” on a Mac running Yosemite. The feature extends to most Apple apps including Mail, Safari, Pages, Numbers, Keynote, Maps, Messages, Reminders, Calendar, and Contacts.
But as Berlin-based security researcher Jeffrey Paul discovered, the convenience of syncing documents across multiple Apple devices may come at a hefty price to privacy, with unsaved documents in Yosemite now being uploaded automatically and “silently” to Apple’s servers.
“Syncing data across devices is perfectly reasonable; silently syncing data — via a stop on Apple servers — that I have previously only stored locally is not,” Paul told CSO Australia.
Prior to Yosemite, if documents were produced in, for example, Apple’s TextEdit, they would be stored in ~/Library/Saved Application State/, allowing the user to find the document in the state they left them even if the document was not explicitly ‘saved’. Under that model, they remained local and encrypted if the user was encrypting their hard drive.
Local encryption however is undermined in Yosemite, according to Paul, who noticed that “all of my locally-stored, ‘unsaved’ documents open in my text editor have now been uploaded in full” to Apple’s servers. The same issue applies to third party document creating apps.
In light of the National Security Agency’s surveillance program, PRISM, and the recent hacks on celebrity iCloud accounts, this is a plausible risk. For Paul, Apple’s new cross-device syncing feature meant the possible exposure of “personally identifiable information, seed values, phone call notes, love letters etc”.
Paul first outlined his concerns in a blog post over the weekend that has resonated with other security researchers. Cryptography expert Matthew Green commented: “So Apple is silently uploading your unsaved documents to iCloud? If this is true, it's completely unacceptable.”
It also would seem that unsaved documents that are uploaded to Apple’s servers aren’t deleted from its servers if iCloud Drive is turned off on a Mac — documents only become inaccessible from the device but are not deleted.
“If you turn off the iCloud Drive feature in iCloud preferences or Internet Accounts preferences, your documents and data stored in iCloud Drive are removed from your Mac, and your Mac apps can no longer access them. If you turn iCloud Drive on again, your iCloud documents become available on your Mac,” states in a support document.
CSO Australia has asked Apple for a response to Paul’s report and will update the story if it receives one.
Paul said he hadn’t reported the issue to Apple since the feature was “working as they intended it to”.Read more: Smart Cities deliver Innovation & Security
Nonetheless, the way the feature functions sits uneasily with Apple’s recent messaging around privacy, including a dedicated page to the issue from CEO Tim Cook, explaining that “we believe in telling you up front exactly what’s going to happen to your personal information and asking for your permission before you share it with us.”
Apple was recently criticised for how it shares desktop and Web searches in its latest desktop operating system, Yosemite.
Apple may have fallen short of its goal on this count by implementing a feature that catches users off guard, according to Paul.
“I feel this violates the principle of least surprise; if you take 100 people and have them open TextEdit and open a new window and type in something private and then power down the computer, how many of those 100 would then believe that Apple now has a copy of that data offsite?”
Additionally, Apple could enable the syncing feature without sending data to its cloud.
“Continuity, their cross-device open file syncing feature currently *requires* Bluetooth. It is an actual design limitation that it only works over a short range. There's no reason for those files to leave the room, yet they make a round-trip to Apple's servers.”
This article is brought to you by Enex TestLab, content directors for CSO Australia.