A bug in hosting or how to make money from the air

Greetings!

While foreign companies pay for bugs, Russians say thank you or don’t say anything at all, silently correcting the error found by another person.
I want to share what happened during the August day.
And now closer to the point ...
On one ordinary day on one well-known hosting, I found a bug unpleasant for them (and even very pleasant for us).
With this bug you can achieve such a result (even more, we have nothing to limit, only conscience) ...

we are interested in the balance below, highlighted in a black square, because it can be displayed on webmoney and until recently there was zero.
The fact is that this hoster has an affiliate program, according to which the client transfers the percentages from the people given by him.
With this money you can:

• pay for hosting,
• withdraw money to webmoney,
• transfer to partners

in all previously mentioned transactions, money is debited from the bonus balance.
So with the first they have a problem. Apparently the programmers did not consider it necessary to check the entered data, so we have nothing to interfere with entering a negative amount, and as you remember from the course of higher mathematics, minus to minus gives plus, so if you pay -20 rubles -> +20 rubles will be added to the balance, and now on the numbers:
it was 1287.00 rubles.
pay for -20rub.
we get
1287 - (-20) = 1307rub.
not bad, right?


though here the payment has already been made, as you can see the amount increased by 20 rubles.

You can withdraw only on webmoney.
Remember that it seems like such a trifle in the code (and it was only worth writing about the following)

if (isset ($ _ POST ['money input field for payment']) && ($ _POST ['money input field for payment']> = 0)) {
// transaction can be done
}
else {
echo ("ah ah ah" );
}

can be expensive ...
Of course, I, as a respectable person, notified those. hosting support, but the reaction was not instant, thanks I heard after 4 hours:

“Hello. Thank you for pointing out the error. Your request has been submitted to programmers. We will try to fix the problem as soon as possible. ”
However, the problem was fixed somewhere in a month.