Grindr v2.1.1 iOS - (eMail) Session Vulnerability

[Vulnerability Lab <research () vulnerability-lab com>]

Document Title:
===============
Grindr v2.1.1 iOS - (eMail) Session Vulnerability


References (Source):
====================
http://www.vulnerability-lab.com/get_content.php?id=1426


Release Date:
=============
2015-05-04


Vulnerability Laboratory ID (VL-ID):
====================================
1426


Common Vulnerability Scoring System:
====================================
6.8


Product & Service Introduction:
===============================
Grindr, which first launched in 2009, has exploded into the largest and most popular all-male location-based social 
network out there. 
With more than 5 million guys in 192 countries around the world -- and approximately 10,000 more new users downloading 
the app 
every day -- you’ll always find a new date, buddy, or friend on Grindr. Grindr is a simple app that uses your mobile 
device’s 
location-based services to show you the guys closest to you who are also on Grindr. How much of your info they see is 
entirely your call.

(Copy of the Vendor Homepage: http://grindr.com/learn-more )


Abstract Advisory Information:
==============================
The Vulnerbaility Laboratory Research Team discovered a session vulnerability and a validation issue in the Grindr 
v2.1.1 iOS mobile app api & connected account system.


Vulnerability Disclosure Timeline:
==================================
2015-01-23: Researcher Notification & Coordination (Benjamin Kunz Mejri - Evolution Security)
2015-01-23: Vendor Notification (Grinder - Bug Bounty Program)
2015-02-01: Vendor Response/Feedback (Grinder - Bug Bounty Program)
2015-04-01: Vendor Fix/Patch (Grindr Developer Team - Reward: x  & Manager: x)
2015-05-04: Public Disclosure (Vulnerability Laboratory)


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


Affected Product(s):
====================
Grindr LLC
Product: Grinder - iOS Mobile Web Application (API) 2.2.1


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


Severity Level:
===============
High


Technical Details & Description:
================================
By usage of the mobile iOS app we was able to figure out the following vulnerability. The vulnerability is located in 
the email and old_email values of the service. The encoding and the input validation allows the usage of special chars 
in the client-side (GET) url request which impact the first risk. 

The second risk is that the request can be intercepted by an attacker to manipulate the session values only with an 
existing profileId. The profile id and the email of an user can be captured by usage of the regular frontend service. 
The attacker includes to the request an existing session id and uses the old email profile values to compromise another 
users account. For example an attacker can use the profile id of another users account to change the email to his own 
by usage of the vulnerable values. Attacker can also use empty string and other text formats to confuse the validation 
on email changes to compromise service accounts. In the referer request that opens the old_email the attacker can 
change the full request. By exchanging the old refer in the live request the attacker is able to reset another account 
with new values. Not only the validation itself is broken, the login mechism loads any string or payload that is 
injected to the admin panel. The season for this little connected issue is that there is no input check, input 
restriction and the validation procedure is missing. Even if no @ for example is in the value the context loads which 
is a kind of design issue in the same location.

Request Method(s):
                                [+] GET

Vulnerable Module(s):
                                [+] email > edit

Vulnerable Parameter(s):
                                [+] old_email > email


Proof of Concept (PoC):
=======================
The session data and validation vulnerability can be exploited by remote attackers with privileged application user 
account and low user intaction.
For security demonstration or to reproduce the security vulnerability follow the provided information and steps below 
to continue.

Manual steps to reproduce the security vulnerability ...
1. Request https://account.grindr.com/user/edit?email=test () evolution-sec 
com&profileId=44889459&locale=de&clientVersion=2.1.1
2. Open the connected module after the first request 
https://account.grindr.com/user/email?locale=de&old_email=%20test%40evolution-sec.com&profileId=44889459
3. Change the profileID and use the same email
4. Successful reproduce of the vulnerability!


1.Vulnerability
https://account.grindr.com/user/email?locale=de&old_email=test%40evolution-sec.com&profileId=44889459

2.
https://account.grindr.com/user/edit?email=test () evolution-sec com&profileId=44889459&locale=de&clientVersion=2.1.1
http://grindr.com/app/profile-guidelines?profileId=44889459&lat=51.33772279645419&lon=9.4405975428029


Extended manual steps to reproduce ... (device)
The intercepting of the session from the device to the website needs to be done manually.
I tried it again and it just works well the manual way.

1. Request https://account.grindr.com/user/edit?email=test () evolution-sec 
com&profileId=44889459&locale=de&clientVersion=2.1.1
2. Open the connected module after the first request 
https://account.grindr.com/user/email?locale=de&old_email=%20test%40evolution-sec.com&profileId=44889459
3. Change the profileID and use the same email
4. Successful reproduce of the vulnerability!

Note: Perform two requests and manipulate the https with the values of your test accounts. Then start a session tamper 
to intercept the value in the live request 
by the ios device side to the account system. (install a debugging proxy and point your iPhone - http protocol) Then 
you do not get any error and be successful.

Reference(s):
https://account.grindr.com/user/edit?email=test () evolution-sec com&profileId=44889459&locale=de&clientVersion=2.1.1
https://account.grindr.com/user/email?locale=de&old_email=test%40evolution-sec.com&profileId=44889459
http://grindr.com/app/profile-guidelines?profileId=44889459&lat=51.33772279645419&lon=9.4405975428029


Solution - Fix & Patch:
=======================
1. Disallow to load the url value plain in the old_email parameter
2. Approve the profileID by a valid request that is connected with a unqiue cookie/token
Note: If the context changes after a manipulation it is required that the session expires on referer changes
3. Same must be done in die edit?email to ensure that the followup request does not bypass the internal auth liek in my 
case.


Security Risk:
==============
The security risk of the session vulnerability and validation issue is estimated as high. (CVSS 6.8)


Credits & Authors:
==================
Vulnerability Laboratory [Research Team] - Benjamin Kunz Mejri (bkm () evolution-sec com) [www.vulnerability-lab.com]


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=========================
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