Previously, after providing a victim’s Apple ID and date of birth, an attacker could send a URL to Apple that would change the password for that account, without needing to answer any security questions. In response, Apple blocked access to the password reset page, and a short while later took the entire site down in light of another loophole that still allowed the attack to be performed.
This vulnerability came at an interesting time, just a day after Apple began to roll out its two-step verification system. Users who had already enrolled in the new system seem to have been immune from the password reset vulnerability.
Unfortunately some users were held in a three-day waiting period for enabling two-step verification, while others live in countries where two-step verification is not currently available.
Today’s events serve as an important example of why two-step verification is a good idea. People interested in getting two-step verification set up can find out how with iMore’s tutorial.
Update: Details on how the exploit worked can be found here.