From CNet (and my inbox, as a member of the developer program):

Last Thursday, an intruder attempted to secure personal information of our registered developers from our developer website. Sensitive personal information was encrypted and cannot be accessed, however, we have not been able to rule out the possibility that some developers’ names, mailing addresses, and/or email addresses may have been accessed. In the spirit of transparency, we want to inform you of the issue. We took the site down immediately on Thursday and have been working around the clock since then.

One of my fellow TidBITS writers noted the disruption on our staff list after the site had been down for over a day with no word. I suspected a security issue (and said so), in large part due to Apple’s complete silence – even more than usual. But until they sent out this notification, there were no facts and I don’t believe in speculating publicly on breaches without real information.

Three key questions remain:

  1. Were passwords exposed?
  2. If so, how were they encrypted/protected? A password hash or something insecure for this purpose, such as SHA-256?
  3. Were any Apple Developer ID certificates exposed?

Those are the answers that will let developers assess their risk. At this point assume names, emails, and addresses are in the hands of attackers, and could be used for fraud, phishing, and other attacks.