Over the weekend, celebrities such as Jennifer Lawrence and Kate Upton had private photos leaked online. Now Apple has confirmed speculation that the leak was due to hackers targeting the victims' iCloud accounts:
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.
Of course, whether this constitutes a "breach" or not is a matter of opinion. Apple presumably means that the attackers gained access by correctly guessing the victims' "security questions" rather than employing more technically sophisticated hacking techniques.
But either way, Apple bears some responsibility for these attacks. Security researchers have long known that "security questions" aren't very secure — especially for celebrities whose every personal detail is intensely scrutinized by the public.