WordPress, as you know, is one of the best blogging system loved by search engine. There are tons of customization option available in wordpress and with every update of wordpress software, you will find a new feature integrated just to make it much more accommodating for the blog owner.
Similarly the attack on WordPress sites are on a greater extent. Blogote.com was once attacked with a type of virus which embedded in the homepage, single.php and other template files and the blog used to load with a blank page. Luckily, I was able to sort out the malicious code from the theme template and removed them quickly. But to be on the safer side, you can use this Anti virus Plugin which I am using it right now.
A free plugin which scans your blog template everyday or instantly whenever you need, all your theme files will be scanned and if iframe or malicious virus code are present, then these are detected. The plugin can be helpful for all wordpress blogs and is a recommended blog security tip for wordpress users!