逻辑漏洞
准备环境:
多数DVWA不安全验证这个模块报错,需要修改配置,需要添加如下配置:
配置文件位置:
$_DVWA[ 'recaptcha_public_key' ] = '6LdK7xITAAzzAAJQTfL7fu6I-0aPl8KHHieAT_yJg';
$_DVWA[ 'recaptcha_private_key' ] = '6LdK7xITAzzAAL_uw9YXVUOPoIHPZLfw2K1n5NVQ';
注意:
服务器将改密操作分成了两步,第一步检查用户输入的验证码,验证通过后,服务器返回表单,第二步客户端提交post请求,服务器完成更改密码的操作。但是由于部署环境的原因,这里无法正常显示验证码,但是没有关系,通常我们可以绕过这个验证码。下面我们只对第二部进行分析。
低级
代码:
<?php
if( isset( $_POST[ 'Change' ] ) && ( $_POST[ 'step' ] == '1' ) ) {
//通过判断change,step判断验证码是否正确(不正确执行)
// Hide the CAPTCHA form
$hide_form = true;
// Get input
$pass_new = $_POST[ 'password_new' ];
$pass_conf = $_POST[ 'password_conf' ];
// Check CAPTCHA from 3rd party
$resp = recaptcha_check_answer(
$_DVWA[ 'recaptcha_private_key'],
$_POST['g-recaptcha-response']
);
// Did the CAPTCHA fail?
if( !$resp ) {
// What happens when the CAPTCHA was entered incorrectly
$html .= "<pre><br />The CAPTCHA was incorrect. Please try again.</pre>";
$hide_form = false;
return;
}
else {
// CAPTCHA was correct. Do both new passwords match?
if( $pass_new == $pass_conf ) {
// Show next stage for the user
echo "
<pre><br />You passed the CAPTCHA! Click the button to confirm your changes.<br /></pre>
<form action=\"#\" method=\"POST\">
<input type=\"hidden\" name=\"step\" value=\"2\" />
<input type=\"hidden\" name=\"password_new\" value=\"{
$pass_new}\" />
<input type=\"hidden\" name=\"password_conf\" value=\"{
$pass_conf}\" />
<input type=\"submit\" name=\"Change\" value=\"Change\" />
</form>";
}
else {
// Both new passwords do not match.
$html .= "<pre>Both passwords must match.</pre>";
$hide_form = false;
}
}
}
if( isset( $_POST[ 'Change' ] ) && ( $_POST[ 'step' ] == '2' ) ) {
//验证那正确执行,进行密码修改
// Hide the CAPTCHA form
$hide_form = true;
// Get input
$pass_new = $_POST[ 'password_new' ];
$pass_conf = $_POST[ 'password_conf' ];
// Check to see if both password match //两次密码是否匹配
if( $pass_new == $pass_conf ) {
// They do!
$pass_new = ((isset($GLOBALS["___mysqli_ston"]) && is_object($GLOBALS["___mysqli_ston"])) ? mysqli_real_escape_string($GLOBALS["___mysqli_ston"], $pass_new ) : ((trigger_error("[MySQLConverterToo] Fix the mysql_escape_string() call! This code does not work.", E_USER_ERROR)) ? "" : ""));
$pass_new = md5( $pass_new );
// Update database 更新数据库
$insert = "UPDATE `users` SET password = '$pass_new' WHERE user = '" . dvwaCurrentUser() . "';";
$result = mysqli_query($GLOBALS["___mysqli_ston"], $insert ) or die