Payment Bypass Allowed Me to Purchase Anything for Free

Hamzadzworm
3 min readOct 30, 2024

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Hi, My name is abdelkader mouaz and also know as Hamzadzworm

“Today, I’ll share an interesting finding that allowed me to shop for anything for free.”

“I received an invite to a private program, but subdomains were out of scope because they said the subdomains belonged to third-party companies.”

“So, I kept digging to find any subdomains owned by the company I was working with.”

And after few hours i got an interesting subdomain that sell products and i noticed that in this products there is logo of company iam working for
so i started working on it

“This subdomain doesn’t have many functions; you can only shop on it.”

“So, I went straight to trying to manipulate the payment to see if there was anything I could do.”

“Here are some things I tried that you can also test:

  • I attempted to change the product price.
  • I tried to modify the currency.”
  • I tried replacing ‘false’ with ‘true’ in the response.
    I also tried replacing ‘failed’ with ‘success.’”

“None of these worked for me.

After spending some time on it, I went to the cart and started experimenting with the quantity parameter.”

“I tried to calculate a quantity using subtraction (-).”

And result was:

“But since you can’t pay anything with a negative amount (-), I searched for multipe other products to make price =130.

So, (-130) + (130) = 0.

This way, I was able to get a product for free. Then the triager asked me to prove that I was able to place an order successfully by tampering with the price.”

Result:

And they was able to validat my report:

I hope you enjoyed reading that, and I hope you gained some new ideas from my report that may help you in the future.”

All the best. -.-

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