The hackers are inserting hundreds of spammy links that point to drug, credit card and gambling related sites into the header and footer files and then making them not visible when viewing your blog page with a simple CSS manipulation.
There has been an outburst of blog hack attacks recently. The main focus of the blog hack attacks is older versions of the free Wordpress blogs that are less than the latest 2.5 version release.
It is rife, it is rampant, its a really big problem and the majority of everyday bloggers or online marketing types don't have a clue they have been hacked and infected with spammy links that will punish their site and any site that is affiliated via links inbound or outbound.
Beefing Up Blog Security
A few things you should do straight away is to upgrade your blog to the latest Wordpress 2.5 release. For those that don't have the patience to read through here's a quick simplified guide:
Download and unzip Wordpress 2.5
Back-up your Blog files onto your local drive
Turn off all plugins
Delete the wp-admin and the wp-includes folder on your server
Upload the new Wordpress 2.5 wp-admin and wp-includes folder
Delete the index.php file in the wp-content folder and then upload the index.php file from the wp-contact folder in your 2.5 release
Delete all top level files except your wp-config file and replace with top level files from the 2.5 release - Remember don't overwite your wp-config file your database info is kept in here
That's it you are done! Just re-enable your plugins from earlier and your back up and running as per normal.
They Got IN Now What?
First step is to remove the inserted links: they usually go for the header and footer files. Next alert Google by logging into Google Webmaster Tools (if you don't have an account then create one it only takes 2 minutes) and click the link on the right hand side titled "Request reconsideration".
Explain in your statement that you have had your blog hacked and the links have now been removed and the site is clean. Back up your claim by detailing where the spammy links where residing in your code i.e. they start at line 200 or just under the body tag. It may seem obvious but you must consider you are presenting proof to clear your site and your name. Finally, also add what impediment steps you have taken to help beefen up security.
Watch who you link out too!
A hacked site will have some penalties against it: in Google's eyes you'll be what is termed as a bad neighborhood.
