Banco Guayaquil v8.0.0 iOS - Cross Site Web Vulnerability

Document Title:
===============
Banco Guayaquil v8.0.0 iOS - Cross Site Web Vulnerability


References (Source):
====================
https://www.vulnerability-lab.com/get_content.php?id=2315


Release Date:
=============
2022-01-21


Vulnerability Laboratory ID (VL-ID):
====================================
2315


Common Vulnerability Scoring System:
====================================
4.6


Vulnerability Class:
====================
Cross Site Scripting - Persistent


Current Estimated Price:
========================
500€ - 1.000€


Product & Service Introduction:
===============================
Official application of Banco Guayaquil to manage your finances your products with Banco Guayaquil, Make transactions 
from your accounts, Pay credit cards, loans and services as well as access your movements, Deposit checks, Request 
checkbooks, block cards, activate or deactivate consumption of the Internet and much more.

(Copy of the Homepage: https://apps.apple.com/ec/app/banco-guayaquil/id624963066)


Abstract Advisory Information:
==============================
An independent vulnerability laboratory researcher discovered a persistent cross site web vulnerability in the official Banco Guayaquil 8.0.0 mobile ios app.


Affected Product(s):
====================
Banco de Guayaquil
Product: Banco Guayaquil v8.0.0 - Apple iOS (Web-Application)


Vulnerability Disclosure Timeline:
==================================
2022-01-21: Public Disclosure (Vulnerability Laboratory)


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


Exploitation Technique:
=======================
Local


Severity Level:
===============
Medium


Authentication Type:
====================
Restricted Authentication (User Privileges)


User Interaction:
=================
No User Interaction


Disclosure Type:
================
Independent Security Research


Technical Details & Description:
================================
An application-side input validation  vulnerability has been discovered in the official Banco Guayaquil 8.0.0 mobile ios application.
The vulnerability allows a local attacker to inject own script code as payload to the application-side of the vulnerable service 
function or module. The vulnerability is located in the TextBox Name Profile input. The code executes after input on any review 
after the application start. The attack vector of the vulnerability is persistent and the request method to inject is POST.

Request Method(s):
[+] Import

Vulnerable Module(s):
[+] Add Name

Vulnerable Parameter(s):
[+] TextBox Name Profile

Vulnerable Final(s):
[+] Save Profile


Proof of Concept (PoC):
=======================
The persistent input validation web vulnerability can be exploited by local attackers with system user account and without user interaction.
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. Install the ios application to your ios device (https://apps.apple.com/ec/app/banco-guayaquil/id624963066)
2. Add new name as profile with the script code payload in the TextBox Name input
3. Save Profile via submit
4. Close mobile application to restart
5. Open mobile ios aplication again
6. Now the context executes directly on review without interaction
7. Successful reproduce of the persistent web vulnerability!


Proof of Concept (IMAGES):
https://i.imgur.com/Cc1VFUf.png
https://i.imgur.com/r1HWwrs.png


Proof of Concept (VIDEO):
https://imgur.com/a/lQHt1br

Payload: Cross Site Scripting
Use Breaks JS Context: <object data>, javascript:alert, <img onerror>
text/html;base64,PHNjcmlwdD5hbGVydCgiVnVsbmVyYWJsZSIpOzwvc2NyaXB0Pg


Solution - Fix & Patch:
=======================
The vulnerability can be resolved by a encode and secure parse / escape of the inputs.
In a second step the output location were the execute occurs needs to be sanitized.


Security Risk:
==============
The security risk of the persistent validation web vulnerability in the mobile ios web-application is estimated as medium.


Credits & Authors:
==================
TaurusOmar [[email protected]] - https://www.vulnerability-lab.com/show.php?user=TaurusOmar


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