According to Carole Theriault, senior security consultant at Sophos, this should act as a warning to computer users to regularly change passwords and use different passwords for separate sites.
"Given the ever growing popularity of online gaming in China, this is a worrying trend - once hackers have stolen login details, they can effectively impersonate the victim in the online world," she said.
"Millions of people play these games every day, but once inside the game, it's difficult to check their identity and these cyber criminals can wreak havoc, for example buying and selling items in online stores and running up huge debts without the victim even realising," she continued.
Theriault added that while cyber criminals hacking into an instant messaging system may not appear to be a major concern, users should be worried.
"The danger is that the cyber criminals will have inadvertently gained access to bank accounts, or cracked the passwords to secure password protected information," she said.