i'm glad that one of our plurk friends and ka-network shared this shocking news that WP is under attack, and it affects only the ones who got the old version of WP. To avoid this, you should upgrade your WP and back up your blog. I know that this will happen as there are some reports of WP blog hijacking last week. Same thing that happened to blogger.com that was under DDOS attack.
for more details and information, read the news here at Security Threat: WordPress Under Attack
I went on a panic this morning, and upgraded immediately, I read the news last night and I didn't seem to mind at it. but then this morning, I remembered that I run 2 big WP blogs from a client, then I set up an action and did some test..and glad that it is safe.
our fellow blogger-plurker friend Paul Pajo, shared his article How to keep you WordPress blog secure