Buuctf, web:[geek challenge 2019] buyflag

attention

If you want to buy the FLAG:
You must be a student from CUIT!!!
You must be answer the correct password!!!

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Only Cuit's students can buy the FLAG

Three tips , buy , use money=100000000, It's a CUIT Of the students , Correct password

Source code

	~~~post money and password~~~

if (isset($_POST['password'])) 
{
	$password = $_POST['password'];
	if (is_numeric($password)) 
    {
		echo "password can't be number</br>";
	}
    elseif ($password == 404) 
    {
		echo "Password Right!</br>";
	}
}

Weak comparison

password=404a

This is the code

Grab the bag post Still no response , The second tip is useless , Students can only correspond to cookie Of user

  Change it to 1

Three conditions meet two ,money The parameter is too long

Use scientific counting method to get flag, Operation not available  

 

 flag{baf3e10e-319b-4315-a300-09be81b69856}