CNZZ Data Breach

Contemporary Chinese reporting named CNZZ in a wave of password leaks affecting numerous internet services in December 2011. A later breach catalog dates the event to February 2012. Because the sources do not establish the exact date of initial access, the catalog uses month precision and does not present February 2012 as a conclusively established intrusion date.

The presence of CNZZ-specific database files and contemporary reporting linking the organization to the leak wave support the dataset's CNZZ attribution. However, a broader follow-up published in January 2012 did not separately list CNZZ among the incidents officially confirmed at that time. The 945,054 figure is therefore a source-reported total; the exact intrusion date and initial access method remain undetermined in public sources.

The reported fields are usernames, email addresses and password hashes. The passwords were reportedly stored using MD5. MD5 is not considered adequate for password storage today, and short or reused passwords may be more vulnerable to offline guessing attacks.

If a password used on CNZZ was reused elsewhere, those accounts should be changed to strong, unique passwords. Multi-factor authentication should be enabled wherever available, and unexpected password-reset or account-verification messages sent to older email addresses should be checked by visiting the relevant service's official website directly.