iOS 8 Protection Mode Bug: Some User Files At Risk of Exposure

Apple’s recent security announcement suggested that they no longer have the ability to dump your content from iOS 8 devices:

“On devices running iOS 8, your personal data such as photos, messages (including attachments), email, contacts, call history, iTunes content, notes, and reminders is placed under the protection of your passcode. Unlike our competitors, Apple cannot bypass your passcode and therefore cannot access this data. So it’s not technically feasible for us to respond to government warrants for the extraction of this data from devices in their possession running iOS 8.”

It looks like there are some glitches in this new encryption scheme, however, and some of the files being stored on your iOS 8 device are not getting encrypted in this way. If you copy files over to your device using iTunes’ “File Sharing” feature or sync videos that appear in the “Home Videos” section of iOS, these files are not getting placed under the protection of your passcode. Theoretically, Apple could dump these in Cupertino, if given your locked iPhone.

As I pointed out in recent blog post, law enforcement forensics tools can still dump a lot of data from iOS 8 devices too, if they seize your desktop/laptop and copy a pairing record. There was one caveat to this, however, and that was if your device was shut off, they could not get to any of that data until the user entered their passcode again. It looks like, due to this glitch, at least some files are accessible, even if the device has been powered down.

This all came out of a brief discussion this morning with a fellow colleague in the forensics world, Kevin DeLong, who has been teaching forensics investigation classes for years now. He noted that one of the tools he’s been using, iFunbox (a freeware tool to access data on your iPhone), was somehow able to access some of his application files even after rebooting his phone. This conflicted with what we know about the escrow bag stored in pairing files, which normally can’t unlock encryption after a device is rebooted, until the user first enters their passcode. After doing some protocol-level testing, I was able to reproduce this, as well as identify a number of files in iOS 8 that are getting assigned the wrong protection class, and do not get encrypted with with keys dependent on the passcode, as Apple claims.

This is likely just a bug, and I suspect once Apple understands what’s going on, they’ll issue a fix. But for now, it’s important to note that the following data may be at risk under certain circumstances (such as being detailed at an airport, even if you shut your phone down).

  • Any files copied over from iTunes using “File Sharing”  under “Apps”.
  • Any videos copied in from iTunes that fall under the “Home Videos” section of the Videos app. This likely extends to music videos and movies.
  • Any databases stored in Third Party applications are protected, but their -shm (shared-memory write-ahead index) counterpart files are at risk.

Apple has not given any indication that they would be willing to dump this information on behalf of law enforcement, but until they fix the protection classes that these files are assigned, the technical possibility exists to copy this data off without having the passcode.

Take appropriate steps to protect your data. To protect yourself from forensics tools, follow these instructions to pair lock your iOS device, so that a new pairing cannot be created, even if you’re compelled to give up your passcode. Encrypt your desktop/laptop so that pairing files cannot be copied off while it is properly shut down.

I have filed this bug with Apple as bug #18439395.