GhostMail Status Message HTML Injection

`Document Title:  
===============  
GhostMail - (Status Message) Persistent Web Vulnerability  
  
  
References (Source):  
====================  
http://www.vulnerability-lab.com/get_content.php?id=1470  
  
  
Release Date:  
=============  
2018-06-27  
  
  
Vulnerability Laboratory ID (VL-ID):  
====================================  
1470  
  
  
Common Vulnerability Scoring System:  
====================================  
4  
  
  
Vulnerability Class:  
====================  
Script Code Injection  
  
  
Current Estimated Price:  
========================  
1.000a! - 2.000a!  
  
  
Product & Service Introduction:  
===============================  
Sign up to military grade encrypted GhostMail and enjoy instant free and  
secure email & chat. No download or installs needed.  
GhostMail is your new secure email & chat platform, with great features  
like self destruction, two factor login and much more...  
Join free today and start enforcing your privacy and online rights.  
  
(Copy of the Vendor Homepage: https://www.ghostmail.com/ )  
  
  
Abstract Advisory Information:  
==============================  
The vulnerability laboratory core research team discovered an  
application-side vulnerability in the official GhostMail chat online  
service web-application.  
  
  
Vulnerability Disclosure Timeline:  
==================================  
2018-06-27: Public Disclosure (Vulnerability Laboratory)  
  
  
Discovery Status:  
=================  
Published  
  
  
Affected Product(s):  
====================  
GhostCom Ltd.  
Product: GhostMail (Chat) - Web Application (Online Service) 2015 Q2  
  
  
Exploitation Technique:  
=======================  
Remote  
  
  
Severity Level:  
===============  
Medium  
  
  
Authentication Type:  
====================  
Restricted authentication (user/moderator) - User privileges  
  
  
User Interaction:  
=================  
Low User Interaction  
  
  
Disclosure Type:  
================  
Bug Bounty Program  
  
  
Technical Details & Description:  
================================  
An application-side html injection web vulnerability has been discovered  
in the official GhostMail chat web-application.  
The vulnerability allows to inject unauthorized malicious script codes  
on the application-side of the affected module.  
  
The issue exists in chat status of the application and is remotly  
exploitable against other ghostmail user accounts.  
The request method to inject is POST and the attack vector is located on  
the application-side of the affected online  
service web-application. The encoding of the status message in the chat  
client is broken. Local and remote attackers  
can use the lack of validation to perform html injection attacks to  
compromise user/moderator/admin session data.  
  
The security risk of the html injection web vulnerability is estimated  
as medium with a cvss count of 4.0.  
Exploitation of the issue requires a low privileged web-application user  
account and no direct user interaction.  
Successful exploitation of the application-side vulnerability results in  
session hijacking, persistent phishing,  
persistent external redirects and persistent manipulation affected or  
connected module context.  
  
Vulnerable Domain(s):  
[+] Ghostmail.com  
  
Vulnerable Module(s):  
[+] Status Message  
  
Vulnerable Parameter(s):  
[+] Status message body context  
  
  
Proof of Concept (PoC):  
=======================  
The html injection web vulnerability can be exploited by local and  
remote attackers with low user interaction and low privileged  
application user account.  
For security demonstration or to reproduce the security vulnerability  
follow the provided information and steps below to continue.  
  
Manual Steps to reproduce the vulnerability ...  
1. Register an account and login to the ghostmail application  
2. Move to the chat status contents  
3. Close the tag of title with double quote "  
4. Now, add a new malicious content as payload in the status title for  
the chat  
5. Start to chat and in the same moment the execution of the script code  
occurs at both party sides of the client  
6. Successful reproduce of the vulnerability!  
  
Note: There is no filter validation or mechanism in place to prevent an  
execution within the ghostmail web-application.  
  
Reference(s):  
https://www.ghostmail.com/  
  
  
Solution - Fix & Patch:  
=======================  
The vulnerability can be patched by a parse and encode of the vulnerable  
status mesage in the ghostmail chat client.  
The issue has been reported in 2016 Q4 (2016-10-01) and was finally  
resolved in 2017 Q3 - Q4 by the ghostmail developer team.  
  
  
Security Risk:  
==============  
The security risk of the application-side input validation web  
vulnerability in the chat module is estimated as medium (CVSS 4.0).  
  
  
Credits & Authors:  
==================  
Vulnerability-Lab [[email protected]] -  
https://www.vulnerability-lab.com/show.php?user=Vulnerability-Lab  
  
  
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=========================  
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