This week news broke that private pictures belonging to several popular celebrities had been obtained by an individual who then posted these pictures on 4chan. They were then linked to, and widely discussed, across many media outlets. Initial speculation and discussion as to how this content was obtained suggested it was done through vulnerabilities in the Find My iPhone app, or with iCloud itself, strongly implying that access to these pictures was gained because of a technical flaw or vulnerability which was exploited by a "hacker".
Apple released the following statement on September 2:
Update to Celebrity Photo Investigation
We wanted to provide an update to our investigation into the theft of photos of certain celebrities. When we learned of the theft, we were outraged and immediately mobilized Apple’s engineers to discover the source. Our customers’ privacy and security are of utmost importance to us. After more than 40 hours of investigation, we have discovered that certain celebrity accounts were compromised by a very targeted attack on user names, passwords and security questions, a practice that has become all too common on the Internet. None of the cases we have investigated has resulted from any breach in any of Apple’s systems including iCloud® or Find my iPhone. We are continuing to work with law enforcement to help identify the criminals involved.
To protect against this type of attack, we advise all users to always use a strong password and enable two-step verification. Both of these are addressed on our website at http://support.apple.com/kb/ht4232.
Apple's assertion that a "very targeted attack on user names, passwords and security questions, a practice that has become all too common on the Internet" isn't a flaw in their system is both correct and incorrect. This blog often discusses vulnerabilities of sites and apps that are not properly protected by strong 2-factor and multi-factor authentication. In this case, Apple's system was not able to identify the true account owner, even when correct credentials were provided, and correct answers were given to security questions. That is a flaw, especially since technology is available to address this use case, including biometrics, advanced device identification techniques, and external multi-factor authentication. Mashable says "...Although Apple might be technically correct in that its own systems weren't breached, the fact that this type of "ripping" process is so common on the underground certainly raises questions about the overall security (or at the very least, education) of iCloud's systems."
In fairness to Apple and iCloud, this is a vulnerability that exists across many, many sites and cloud based offerings. It isn't specific to iCloud. iCloud is the example - this time - but it's an example of a much bigger problem. Cloud providers should take this incident as a warning, and a critical use case, and work to address the question "are you who you say you are" every time an account is accessed.