"The intruder was able to access forum user profiles, which include the email addresses connected to those forum accounts," said Sandbox Interactive GmbH, the company behind Albion Online.
The attacker also harvested encrypted passwords. Sandbox Interactive said the passwords were hashed with the Bcrypt password-hashing function and then salted with random data to make it harder for attackers to reverse and crack the password.
"These can NOTbe used to log in to Albion Online, the website
or the forum, nor can they be used to learn the passwords themselves," the German game maker said.
"However, there is a small possibility they could be used to identify accounts with particularly weak passwords."
Users who reused emails and passwords for both their game and forum account are at particular risk.
As a result of the unauthorized intrusion, the game maker asked forum users to reset passwords via a forum post on Saturday, and emails delivered to all impacted users.
The company did not disclose the size of the breach.
Sandbox Interactive said the intrusion took place on Friday, October 16, and the attacker utilized a vulnerability in its forum platform, known as WoltLab Suite.