iPhone thieves may still be able to access iMessages sent to the victim's replacement device, thanks to a bug on Apple's flagship smartphone.
iMessages is an Apple proprietary system for iOS 5 and an alternative to SMSes that allows iPhones to send text and multimedia for free over a data network.
The flaw, first reported by users on web forums after the October release of iOS 5, appears to bind a victims' iMessages to an iPhone once the service was activated.
Phone numbers and Apple IDs must be registered to use the service, a requirement that may contribute to the privacy breach.
The bug persisted even after a firmware restore, Ars Technica reported.
Apple has declined to comment on the security issue.
The effect of the flaw was graphically demonstrated by Gizmodo after it published a series of raunchy text messages and lewd photographs sent and received by an Apple engineer who fell victim to the flaw.
It appeared the engineer had inserted and later removed his SIM card while repairing a customers’ iPhone.
The iMessages continued to arrive after the iPhone's firmware was restored.
iOS security expert and senior forensic scientist with viaForensics, Jonathan Zdziarski, told Ars Technica the issue may arise if the affected iPhone read from a cache containing the user's Apple ID and phone number, built when iMessage was first registered.
He said this could explain why the bug persisted after a firmware restoration.