“What was interesting about this threat wasn't just the sheer number of stolen accounts, but that the accounts were being validated by a trojan [detected by Symantec as Trojan.Loginck] distributed to compromised computers,” Eoin Ward, anti-virus researcher and security response engineer at Symantec, wrote in a blog post Wednesday.
The malware was developed to log into the database and download a group of usernames and passwords to check them for validity. The trojan-based validation allows attackers to check the accounts more quickly than trying to manually log into the accounts.
If the trojan successfully logs into an account, it will update the database with the time it logged in and the current game level of the account.
Gaming account credentials can be valuable if the accounts are valid. This is because the assets that a player accumulates in the games, such as weapons and armor, are worth real-world dollars.
The market value of online gaming accounts can range from less than $10 to several thousand dollars, depending on how advanced an account is.
The database contains 16 million stolen account credentials for Wayi Entertainment, two million for Play NC, 210, 000 for World of Warcraft, and 60,000 for Aion. Symantec recommended that users of the affected sites change their passwords.