Warframe creator Digital Extreme has revealed that a list containing 775,749 player email addresses was stolen in November 2014.

The news is only just coming to light because the developer initially believed the theft was a phishing scam, as its account server was secure at the time.

After conducting a "thorough review" of the data it's received, Digital Extreme broke the news to players in a forum post.

"Last week we were made aware of a potential web server breach that occurred in November 2014," reads the message.

"We can confirm that a list of 775,749 email addresses were acquired through a Drupal SQL exploit that was patched by Drupal two weeks after the breach occurred."

Although a lot of emails were taken, the studio has emphasized that the stolen data didn't include any account passwords or personal information; such as names, addresses, or billing info of any kind. 

The developer has assured players it will continue to improve its security measures and plug and exploits it unearths.