Nintendo headquarters in Kyoto announced today its member rewards site Club Nintendo has been hacked, following the discovery of a number of access errors that have appeared on the website since July 2.
According to the publisher (as translated by Kotaku), roughly 23 thousand unauthorized log-in were noted between June 9 and July 4 on Japan's Club Nintendo, with 15 million attempts at entering the site. As credit cards are not used with Club Nintendo, these have not been compromised; however, full names of members, along with their home addresses, phone numbers and mail addresses are potentially at risk.
Nintendo is in the process of strengthening its security. Current Club Nintendo members throughout Japan are now being asked to change their passwords as old passwords are now invalid.
This does not appear to affect users outside of Japan.