{"id":105,"date":"2026-04-05T07:26:29","date_gmt":"2026-04-05T07:26:29","guid":{"rendered":"https:\/\/stories.secone4all.com\/?p=105"},"modified":"2026-04-08T06:32:35","modified_gmt":"2026-04-08T06:32:35","slug":"how-i-discovered-critical-price-manipulation","status":"publish","type":"post","link":"https:\/\/stories.secone4all.com\/index.php\/2026\/04\/05\/how-i-discovered-critical-price-manipulation\/","title":{"rendered":"How I discovered critical price manipulation"},"content":{"rendered":"\n

Hello Brothers, <\/p>\n\n\n\n

I hope you have a nice day. Today I will share how I discovered price manipulation.<\/strong><\/p>\n\n\n\n

During my holiday, I started testing on a private program. The first thing I did was browse my target and try to discover the site’s features. After some time of browsing the target, I went to the payment page and started testing the payment functionality.<\/strong><\/p>\n\n\n\n

There are 3 payment plans, as shown below in the image.<\/strong>

<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n
    \n
  1. Annual Plan, Pay upfront. This plan by default offers 20% off.
    <\/li>\n\n\n\n
  2. Annual Plan, Monthly Payment. This plan by default offers 10% off, and the coupon that applied the 10% off exists in the URL.<\/li>\n\n\n\n
  3. Monthly. This plan does not offer any discount.<\/li>\n<\/ol>\n\n\n\n

    <\/p>\n\n\n\n

    Now we understand the 3 types of plans, let’s go to the exploitation.<\/p>\n\n\n\n

      \n
    1. First, I switched to the Annual Plan, Monthly Payment plan. I noticed that the coupon_id appears in the URL, as shown below.<\/li>\n<\/ol>\n\n\n\n
      \"\"<\/figure>\n\n\n\n

      After that, I switched back to the Annual Plan, Pay upfront plan and Fill all fields and clicked on next.<\/p>\n\n\n\n

      \"\"<\/figure>\n\n\n\n

      Then I added the Coupon_id parameter to the URL. I noticed that we can apply 30% off on this plan. By default, this plan allows only 20% off, but using this way I was able to apply 30% off, leading to more significant loss for the company.<\/p>\n\n\n\n

      Note: When I tried to use the Coupon_id parameter on an unauthorized plan, this didn\u2019t work. But many times I noticed that we can use it on an unauthorized plan if we enter payment details and click on next , then append the Coupon_id to the URL. Otherwise, the PoC doesn\u2019t work.<\/p>\n\n\n\n

      This is the response from the customer.
      <\/p>\n\n\n\n

      \"\"<\/figure>\n\n\n\n

      Unfortunately This reward is one of many rewards that I was not able to receive, due to my payment profile and my Bugcrowd account being blocked because of unintentionally breaking the payment policy.<\/p>\n\n\n\n

      Thank you, brothers. I hope this was useful for you.<\/strong> \ud83d\udc4d<\/p>\n\n\n\n