开发笔记:php代码审计题目

php
if ("POST" == $_SERVER[‘REQUEST_METHOD‘])
{
$password = $_POST[‘password‘];
if (0 >= preg_match(‘/^[[:graph:]]{12,}$/‘, $password))
{
echo ‘Wrong Format‘;
exit;
}
while (TRUE)
{
$reg = ‘/([[:punct:]]+|[[:digit:]]+|[[:upper:]]+|[[:lower:]]+)/‘;
if (6 > preg_match_all($reg, $password, $arr))
break;
$c = 0;
$ps = array(‘punct‘, ‘digit‘, ‘upper‘, ‘lower‘);
foreach ($ps as $pt)
{
if (preg_match("/[[:$pt:]]+/", $password))
$c += 1;
}
if ($c <3) break;
if ("42" == $password)
require ‘flag鏂囦欢‘;
else echo ‘Wrong password‘;
exit;
}
}

PHP在判断相等时做出的变化
var_dump("1" == "01"); // 1 == 1 -> true
var_dump("10" == "1e1"); // 10 == 10 -> true
var_dump(100 == "1e2"); // 100 == 100 -> true