Basic Steps for Increasing the Security of your Account
Please ensure that:
* Your password is difficult to guess, use random numbers and letters and avoid anything too obvious
* You do not share your account details with anyone
* You do not store sensitive account information on your computer
* You do not write down your account details where someone may easily find them
* You never give your password to anyone, in game, via email or otherwise. No blizzard employee will ever ask you for your account password
* You never post your account name or email address on our forums, or any other forum
* Any addons you may be using do not contain an executable (.exe) file as these can often be malicious programs designed to steal your account information
* You avoid entering your account details on websites claiming to offer free gold or other in game incentives
* The security of the computer you are using is not compromised in any way, especially when playing in public places or other places where computer access is shared
*information from blizzard*
Also we highly recommend the official
Blizzard authenticator!