From MMORPG.com :
World of Warcraft : Potential Trojan Warned
We’ve been receiving reports regarding a dangerous Trojan that is being used to compromise player’s accounts even if they are using an authenticator for protection. The Trojan acts in real time to do this by stealing both your account information and the authenticator password at the time you enter them.
If your account has been compromised recently, I’d recommend looking for the Trojan. It can be identified by creating an MSInfo file and then looking in the Startup Program section of that file for either “Disker” or “Disker64”. It will usually appear like this:
Disker rundll32.exe c:\users\name\appdata\local\temp\w_win.dll,dw Name-PC\Name Startup
Disker64 rundll32.exe c:\users\name\appdata\local\temp\w_64.dll,dw Name-PC\Name Startup
We are currently looking for more information on the Trojan. We have not been able to locate any anti-virus programs that will remove it besides just reformatting your system. If you have been recently compromised and find it on your system please reply with the following pieces of information.
Your MSInfo.
A list of any addons you recently installed along with where you got them.
A list of any programs you recently installed along with where you got them.
Any security programs you have run and their results.
More info: http://us.battle.net/wow/en/forum/topic/11041384892?page=1