Security Advisory - Curesec Research Team

1. Introduction

Affected Product:    FUDforum 3.0.6
Fixed in:            not fixed
Fixed Version Link:  n/a
Vendor Website:      http://fudforum.org/forum/
Vulnerability Type:  XSS, Login CSRF
Remote Exploitable:  Yes
Reported to vendor:  04/11/2016
Disclosed to public: 11/10/2016
Release mode:        Full Disclosure
CVE:                 n/a
Credits              Tim Coen of Curesec GmbH

2. Overview

FUDforum is forum software written in PHP. In version 3.0.6, it is vulnerable
to multiple persistent XSS issues. This allows an attacker to steal cookies,
inject JavaScript keyloggers, or bypass CSRF protection. Additionally, FUDforum
is vulnerable to Login-CSRF.

3. Details

XSS 1: Via Filename in Private Message

CVSS: Medium 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N

Description: The filename of attached images in private messages is vulnerable
to persistent XSS.

Proof of Concept:

Send a PM to a user. Add an attachment, where the filename is: '"><img src=no
onerror=alert(1)>.jpg When the recipient views the PM, the injected code will
be executed.

XSS 2: Via Filename in Forum Posts

CVSS: Medium 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N

Description: The filename of attached images in forum posts is vulnerable to
persistent XSS.

Proof of Concept:

Create a new forum post. Add an attachment, where the filename is: '"><img src=
no onerror=alert(1)>.jpg When viewing the post the injected code will be
executed.

XSS 3: Via Signature in User Profile

CVSS: Medium 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N

Description: When editing a profile, the signature is echoed unencoded, leading
to persistent XSS.

Proof of Concept:

Visit http://localhost/fudforum/index.php?t=register as signature, use '"></
textarea><img src=no onerror=alert(1)> The injected code is either executed
when the user themselves edits their profile - which may be exploited via login
CSRF - or when an admin visits the edit profile page located here: http://
localhost/fudforum/index.php?t=register&mod_id=6&&SQ=
1a85a858f326ec6602cb6d78d698f60a

Login CSRF

CVSS: Low 2.6 AV:N/AC:H/Au:N/C:N/I:P/A:N

Description: The login of FUDForum does not have any CSRF protection. The
impact of this is low, but an attacker might get a victim to disclose sensitive
information by using CSRF to log the victim into an attacker-controlled
account. An example would be the accidental sending of a sensitive private
message while being logged into an account controlled by an attacker.
Additionally, Login-CSRF may enable an attacker to exploit XSS issues in the
user area.

Proof of Concept:

<html> <body> <form action="http://localhost/fudforum/index.php?t=login" method
="POST"> <input type="hidden" name="login" value="admin" /> <input type=
"hidden" name="password" value="admin" /> <input type="hidden" name="SQ" value=
"0" /> <input type="hidden" name="adm" value="" /> <input type="submit" value=
"Submit request" /> </form> </body> </html>

4. Solution

This issue was not fixed by the vendor.

5. Report Timeline

04/11/2016 Informed Vendor about Issue (no reply)
09/14/2016 Reminded Vendor (no reply)
11/10/2016 Disclosed to public


Blog Reference:
https://www.curesec.com/blog/article/blog/FUDforum-306-Multiple-Persistent-XSS-amp-Login-CSRF-169.html
 
--
blog:  https://www.curesec.com/blog
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Curesec GmbH
Curesec Research Team
Josef-Orlopp-Straße 54
10365 Berlin, Germany