Blizzard has issued a security warning after MMO World of Warcraft suffered from an increase in unauthorised account logins.
Two days ago Blizzard took the web and mobile auction house offline to perform emergency maintenance after players reported they had lost in-game items and gold.
As WoW Insider reported, players found the Mobile Armoury had been used to spend large amounts of their gold on extremely overpriced white-quality items on the auction house - a way to launder gold to the posting player.
Today Blizzard confirmed it had detected a recent increase in unauthorised account logins from its website and the World of Warcraft Mobile Armoury app.
Blizzard is in the process of emailing those who were not using an authenticator and whose accounts suffered unauthorised access to request an account reset. Customer support will restore in-game items and gold to accounts affected, it said.
In a post on Battle.net Blizzard said no account security is guaranteed, and encouraged players to change their password periodically to add another defensive barrier.
"At this time we have no reason to believe that accounts currently using an authenticator are at risk," a customer service representative added.
Blizzard resolved the "website bug" on Monday morning, but access to the auction house via the Mobile Armoury app remains offline while it investigates.