Month: October 2013

Thoughts on iMessage Integrity

Recently, Quarkslab exposed design flaws[1] in Apple’s iMessage protocol demonstrating that Apple does, despite its vehement denial, have the technical capability to intercept private iMessage traffic if they so desired, or were coerced to under a court order. The iMessage protocol is touted to use end-to-end encryption, however Quarkslab revealed in their research that the asymmetric keys generated to perform this encryption are exchanged through key directory servers centrally managed by Apple, which allow for substitute keys to be injected to allow eavesdropping to be performed. Similarly, the group revealed that certificate pinning, a very common and easy-to-implement certificate chain security mechanism, was not implemented in iMessage, potentially allowing malicious parties to perform MiTM attacks against iMessage in the same fashion. While the Quarkslab demonstration required physical access to the device in order to load a managed configuration, a MiTM is also theoretically possible by any party capable of either forging, or ordering the forgery of a certificate through one of the many certificate authorities built into the iOS TrustStore, either through a compromised certificate authority, or by court order. A number of such abuses have recently plagued the industry, and made national news[2, 3, 4].

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