Blizzard has issued a wide alert to all 7 million users of World of Warcraft concerning theft of account personal details through keyloggers, malware and scams:

We?d like to make the community aware of a recent account-theft scam that is being circulated through email, game forums, in-game chat, and other mediums. This scam involves fake URLs, or hyperlinks, that once clicked will install harmful ?keylogging? software intended to steal your World of Warcraft account name and password. After the creators of these keyloggers steal this information, they log into your account, immediately change your password to lock you out, and then sell all of your items and transfer all of your gold.

The scam comes in many forms, including URLs advertised as links to class guides, gameplay videos, and in many cases user-interface (UI) modifications. As a general rule, be extremely wary of URLs ending in ?.jpg.html? and ?.scr,? as in many cases the harmful software is being hidden at locations that end with these extensions.

For these reasons, it is very important that players take caution when being directed to outside websites and update the security on their computers accordingly. To secure your computer, we suggest adding some Internet security to your system (for example: a firewall and anti-virus scanner). If you are unsure what security measures to take, discuss the issue of system security with your ISP or a trained Network Administrator for the solution that is right for you.

We also strongly recommend that all players use the Blizzard Launcher to start World of Warcraft. In addition to serving as a portal to the game, the Blizzard Launcher provides greater security for our players against harmful software such as the type discussed here. To learn more about this utility, please visit the Blizzard Launcher Page and check out the Blizzard Launcher FAQ.
https://www.blizzard.com/support/wow/?id=aww01907p1

If you come across a suspicious link or program, please report it here—
https://www.blizzard.com/support/?id=eHacks000

For more information on keeping your account secure and what to do if you feel your account has been compromised, please visit the Account Security page.
https://www.blizzard.com/support/wowbilling/?id=abl01897p