Data Security on Mobile Devices
In Apple iOS we found a powerful and compelling set of security and privacy controls, backed and empowered by strong encryption. However, we also found a critical lack in coverage due to under-utilization of these tools.
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We observed that a surprising amount of sensitive data maintained by built-in applications is protected using a weak “available after first unlock” (AFU) protection class, which does not evict decryption keys from memory when the phone is locked. The impact is that the vast majority of sensitive user data from Apple’s built-in applications can be accessed from a phone that is captured and logically exploited while it is in a powered-on (but locked) state.
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Use of Apple iCloud (unsurprisingly) transmits an abundance of user data to Apple’s servers, in a form that can be accessed remotely by criminals who gain unauthorized access to a user’s cloud account, as well as authorized law enforcement agencies with subpoena power. More surprisingly, we identify several counter-intuitive features of iCloud that increase the vulnerability of this system.
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More critically, we observe that Apple’s documentation and user settings blur the distinction between “encrypted” (such that Apple has access) and “end-to-end encrypted” in a manner that makes it difficult to understand which data is available to Apple. Finally, we observe a fundamental weakness in the system: Apple can easily cause user data to be re-provisioned to a new (and possibly compromised) HSM simply by presenting a single dialog on a user’s phone.
Via Nick Heer:
Maybe there are only bad options, and this is the best bad option that strikes the least worst balance between individual security and mass security. But the compromises seem real and profound — and are, officially, undocumented.
Previously:
- Reminder: iMessage Not Meaningfully E2E
- Where Is End-to-End Encryption for iCloud?
- Cellebrite Can Now Unlock Recent iPhones
