Groupon Taiwan recently announced that a hacker accessed a database containing user names and encrypted passwords, though the company says no credit card numbers, full names, addresses or phone numbers were exposed (h/t The Next Web).

The service has 4.1 million registered users, though Groupon Taiwan isn't saying how many users were affected by the breach.

All users are being sent a formal notification letter, and are being prompted to reset their passwords.

According to Groupon, the breach only affected its services in Taiwan, not in other countries.