How to get access?

Question

PHP

There is this code

<?php
  include('flag.php');
  if(strcmp($_POST['password'], $password) == 0) {
    echo $flag;
  }
?>

<form method="post">
  <input type="password" name="password" placeholder="Enter password">
  <input type="submit" value="Enter">
</form>

How can I get $flag?

Answer 1

So $flag is not set anywhere. I think it swears at you that the variable is not defined?
PS: And I hope the password is stored in encrypted form in some place?
Then before comparing it is necessary to encrypt the entered password in the form for comparison.