An estimated 13 million gamers have been left at greater risk of ID theft following a breach at gaming firm Nexon.

Data including names, usernames, encrypted resident registration numbers and password hashes was exposed as a result of the breach at Nexon, which maintains the popular online role-playing game, Maple Story. The data breach followed a hack on a backup server for Maple Story late last week. Details of the 5 million customers of other games maintained by Nexon were not exposed.

Nexon has promised to bolster its security in the wake of the attack, the Korean Herald reports. In addition, it is offering game items to gamers who change their passwords.

The security flap could hardly have come at a worse time for Nexon, which plans to float its business in little over a week on 6 December.

The breach at Nexon is only the latest in a growing list of security flaps involving video game developers this year, the most notorious of which led to the weeks-long suspension of Sony's PlayStation Network back in April.

Matt Pauker, co-founder of data encryption firm Voltage Security, said the latest breach underlines the fact that gaming security firms need to take security more seriously if they want to retain the trust of their fans.

"This is unfortunately the latest in a string of attacks against gaming sites; hackers have realised that they represent a virtual treasure trove of personal consumer data," Pauker said. "It's time for the gaming companies to realise that security can't be an afterthought. Good security is just as important as good graphics." ®