The recent attacks only affected those of us who hadn’t updated if we had we would have been safe from this attack. Here is the direct Article from WordPress themselves.

Right now there is a worm making its way around old, unpatched versions of WordPress. This particular worm, like many before it, is clever: it registers a user, uses a security bug (fixed earlier in the year) to allow evaluated code to be executed through the permalink structure, makes itself an admin, then uses JavaScript to hide itself when you look at users page, attempts to clean up after itself, then goes quiet so you never notice while it inserts hidden spam and malware into your old posts.

http://wordpress.org/development/2009/09/keep-wordpress-secure/