Security Advisory - Curesec Research Team

1. Introduction

Affected Product: HumHub 1.0.1 and earlier
Fixed in:         1.1.1
Fixed Version     https://www.humhub.org/en/download/default/form?version=1.1.1
Link:             &type=zip
Vendor Website:   https://www.humhub.org/
Vulnerability     XSS
Type:
Remote            Yes
Exploitable:
Reported to       01/10/2016
vendor:
Disclosed to      03/17/2017
public:
Release mode:     Coordinated Release
CVE:              n/a
Credits           Tim Coen of Curesec GmbH

2. Overview

HumHub is a social media platform written in PHP. In version 1.0.1 and earlier,
it is vulnerable to a reflected XSS attack if debugging is enabled, as well as
a self-XSS attack. This allows an attacker to steal cookies, inject JavaScript
keyloggers, or bypass CSRF protection.

3. Details

XSS 1: Reflected XSS

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

Description: When the debug mode is enabled, which it is by default, the
UserSearch parameter is vulnerable to reflected XSS. Additionally, the
resulting error page discloses all cookies - even httpOnly cookies -, and the
contents of the $_SERVER array.

Proof of Concept:

http://localhost/humhub-0.20.0/index.php?UserSearch[last_login]=<script>alert
(1)</script>&r=admin%2Fuser

XSS 2: DOM-based Self-XSS

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

There is a reflected DOM-based self-XSS vulnerability in HumHub. It may be
possible to exploit this issue via ClickJacking in some browsers.

Proof of Concept:

Visit the profile of a user: http://localhost/humhub-0.20.0/index.php?r=
space%2Fspace&sguid=d2f06d0a-47e1-4549-b469-c8a1df48faca In the "What's on your
mind?"-text box enter: '"><img src=no onerror=alert(5)>

4. Solution

To mitigate this issue please upgrade at least to version 1.1.1:

https://www.humhub.org/en/download/default/form?version=1.1.1&type=zip

Please note that a newer version might already be available.

5. Report Timeline

01/10/2016 Informed Vendor about Issue
01/12/2016 Vendor confirms issue
02/10/2016 Vendor requests more time
08/16/2016 Vendor releases partial fix
09/26/2016 Vendor releases fix
03/27/2017 Disclosed to public


Blog Reference:
https://www.curesec.com/blog/article/blog/HumHub-101-XSS-195.html
 
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Curesec GmbH
Curesec Research Team
Josef-Orlopp-StraAe 54
10365 Berlin, Germany