Another site attack

The 12 WordPress sites I run on shared hosting server with Gradwell (located in the UK) were subject to a particular simple but vicious attack: ALL the php WP files, including the plugins files, were modified with the adding of iframe src=”http://gaccess.dynsite.net/blog/wp-content/0wn3d/” style=”display:none” at the end of each file, rendering the affected sites invisible, including the backends!

The modification dates were all 14 December 2010, around 22h25 GMT.

My host provider was very helpful and helped me clean the files.

Have you seen or heard of such an attack before?