Johns Hopkins researchers poke a hole in Apple’s encryption
Researcher Matthew Green from John Hopkins university claims to have found a way through iMessage to intercept messages, photos and encryption key, and this for iOS versions prior to 9.3. This is done by forging TLS certificates and intercepting traffic by pretending to be an Apple server.
The recently released iOS 9.3 is supposed to incorporate the mitigation advise proposed by the researchers and correct this problem.
The paper can be found here:
Dancing on the Lip of the Volcano: Chosen Ciphertext Attacks on Apple iMessage
Our analysis shows that iMessage has significant vulnerabilities that can be exploited by a sophisticated attacker. In particular, we outline a novel chosen ciphertext attack on Huffman compressed data, which allows retrospective decryption of some iMessage payloads in less than 2^18 queries. The practical implication of these attacks is that any party who gains access to iMessage cipher texts may potentially decrypt them remotely and after the fact.
Specifically, we attempt to answer the following question: how secure is Apple iMessage?
To perform our analysis, we derived a specification for iMessage by conducting a partial black-box reverse engineering of the protocol as implemented on multiple iOS and OS X devices.
Also interesting statement in the paper:
Apple stores encrypted, undelivered messages on its servers and retains them for up to 30 days, such messages are vulnerable to any party who can obtain access to this infrastructure, e.g., via court order
Their long-term recommendation to Apple:
Replace the iMessage encryption mechanism. ;-)
The Washington Post wrote about this paper:
Christopher Soghoian, principal technologist at the American Civil Liberties Union, said that Green’s attack highlights the danger of companies building their own encryption without independent review. “The cryptographic history books are filled with examples of cryptoalgorithms designed behind closed doors that failed spectacularly,” he said.
Also funny is this quote from Green:
it scares me that we’re having this conversation about adding back doors to encryption when we can’t even get basic encryption right.
APN - Apple Push Notification