I got a funny challenge from securityoverride.org’s Advanced Level 1.

The challenge is a section of PHP Script.

Following is the script:

 <?php
                $input = trim(getUserInput());
                if(
                    str_split($input) == array(0,0,0,0) ||
                    strcmp($input, “0000”) == 0 ||
                    strcmp($input, “000”) == 0 ||
                    strcmp($input, “00”) == 0 ||
                    strcmp($input, “0”) == 0 ||
                    $input === 0 ||
                    preg_match(“/^[\d]{1,}$/D”, $input)
                )fail_advanced_1();
               
                if($input == “0000”) complete_advanced_1();
   ?>

After a long time thinking,I found that a different equation”$input === 0“,which means Strict comparisons!!!!

So we just need to input “-0″(negative 0)to pass the script!

PHP type comparisons