Weird Hack after Install

Sergey:

Re: TECH #AKG-499589

Was waiting to go through the outstanding issues from install and got the weirdest thing. The site has new items added to the Main Menu and Publishing Menu that say "Hacked by S.W.A.T." and they posted an article with the same title. But I can't see any other evidence of a hack. They obviously hacked the site but didn't see much damage. Help?

Also, still waiting for an answer on:
Are you interested in doing the other things about when Posting Articles (Guest or Registered):

1. Activate/Include “Author Name” and "About Author" section (200 characters) for article postings (Guest or Registered).
2. Activate/Include “Author Picture” (Avatar) when posting an article (Guest or Registered).
3. Activate/Include “Keyword Tags” for articles when posted (Guest or Registered).

Thanks!
Michael