ICANN is looking into an attack on their systems that took place back in November, they have posted an announcement on their website and have said to stay tuned for further updates by checking back.

An email also went out to those using the CZDS:

In order to continue using CZDS, please visit http://czds.icann.org and follow the instructions there to request a new password. We suggest that you take appropriate steps to protect any other online accounts for which you might have used the same username and/or password.

ICANN is investigating a recent intrusion into our systems. We believe a “spear phishing” attack was initiated in late November 2014. It involved email messages that were crafted to appear to come from our own domain being sent to members of our staff. The attack resulted in the compromise of the email credentials of several ICANN staff members.

In early December 2014 we discovered that the compromised credentials were used to access other ICANN systems besides email:

• The Centralized Zone Data System (czds.icann.org)
  The attacker obtained administrative access to all files in the CZDS. This included copies of the zone files in the system, as well as information entered by users such as name, postal address, email address, fax and telephone numbers, username, and password. Although the passwords were stored as salted cryptographic hashes, we have deactivated all CZDS passwords as a precaution. Users may request a new password at czds.icann.org. We suggest that CZDS users take appropriate steps to protect any other online accounts for which they might have used the same username and/or password. ICANN is providing notices to the CZDS users whose personal information may have been compromised.
• The ICANN GAC Wiki (gacweb.icann.org)
  Public information, the members-only index page and one individual user’s profile page was viewed. No other non-public content was viewed.