DVWA Cross Site Request Forgery (CSRF)

CSRF是跨站请求伪造攻击，由客户端发起，是由于没有在执行关键操作时，进行是否由用户自愿发起的确认攻击者通过用户的浏览器来注入额外的网络请求，来破坏一个网站会话的完整性。

比如某网站用户信息修改功能，没有验证Referer也没添加Token，攻击者可以用HTML构造恶意代码提交POST请求，诱骗已经登陆的受害者点击，可以直接修改用户信息

修复建议

• 验证Referer

• 添加token

DVWA Low 级别 CSRF

0、分析网页源代码（路径："D:\phpstudy_pro\DVWA-master\vulnerabilities\csrf\source\low.php"）

<?php

if(isset($_GET['Change'])) { // 检查是否有请求更改密码的动作
// 获取用户输入的新密码和确认密码
$pass_new = $_GET['password_new'];
$pass_conf = $_GET['password_conf'];

// 检查两次输入的密码是否匹配
if ($pass_new == $pass_conf) {
// 密码匹配
// 防止SQL注入，转义新密码字符串
$pass_new = ((isset($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)) ? "" : ""));

// 对新密码进行MD5哈希加密（注意：MD5加密在此处已经过时，不建议用于存储密码）
$pass_new = md5($pass_new);

// 构造SQL更新语句，更新当前登录用户（由dvwaCurrentUser()函数获取）的密码
$insert = "UPDATE `users` SET password = '$pass_new' WHERE user = '" . dvwaCurrentUser() . "';";

// 执行SQL查询
$result = mysqli_query($GLOBALS["___mysqli_ston"], $insert) or die('<pre>' . ((is_object($GLOBALS["___mysqli_ston"])) ? mysqli_error($GLOBALS["___mysqli_ston"]) : (($___mysqli_res = mysqli_connect_error()) ? $___mysqli_res : false)) . '</pre>');

// 如果密码成功更改，则反馈给用户
$html .= "<pre>Password Changed.</pre>";
} else {
// 如果两次输入的密码不匹配，则反馈错误信息
$html .= "<pre>Passwords did not match.</pre>";
}

// 关闭数据库连接
((is_null($___mysqli_res = mysqli_close($GLOBALS["___mysqli_ston"]))) ? false : $___mysqli_res);
}

?>

1、选择DVWA的CSRF，修改密码为111，提交后观察到网站链接发生变化

http://dvwa/vulnerabilities/csrf/?password_new=111&password_conf=111&Change=Change#

观察链接，认为使用get方式提交修改密码参数，只要三个参数符合就可以执行密码修改的操作

2、打开一个新标签页，在地址栏输入http://dvwa/vulnerabilities/csrf/?password_new=111&password_conf=111&Change=Change#，回车后，进入DVWA中并提示Password Changed，修改密码成功。

3、可以通过将长连接转换为短链接的方法，诱使用户点击链接，通过在线工具 转换

DVWA Medium 级别 CSRF

0、分析网页源代码（路径："D:\phpstudy_pro\DVWA-master\vulnerabilities\csrf\source\medium.php"）

<?php

if( isset( $_GET[ 'Change' ] ) ) {
// Checks to see where the request came from
//检查$_SERVER['HTTP_REFERER']，看看请求是否来自包含当前服务器名称$_SERVER['SERVER_NAME']的地址。stripos函数用于查找HTTP_REFERER是否包含服务器名
if( stripos( $_SERVER[ 'HTTP_REFERER' ] ,$_SERVER[ 'SERVER_NAME' ]) !== false ) {
// Get input
$pass_new = $_GET[ 'password_new' ];
$pass_conf = $_GET[ 'password_conf' ];

// Do the passwords match?
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 the database
$insert = "UPDATE `users` SET password = '$pass_new' WHERE user = '" . dvwaCurrentUser() . "';";
$result = mysqli_query($GLOBALS["___mysqli_ston"], $insert ) or die( '<pre>' . ((is_object($GLOBALS["___mysqli_ston"])) ? mysqli_error($GLOBALS["___mysqli_ston"]) : (($___mysqli_res = mysqli_connect_error()) ? $___mysqli_res : false)) . '</pre>' );

// Feedback for the user
$html .= "<pre>Password Changed.</pre>";
}
else {
// Issue with passwords matching
$html .= "<pre>Passwords did not match.</pre>";
}
}
else {
// Didn't come from a trusted source
$html .= "<pre>That request didn't look correct.</pre>";
}

((is_null($___mysqli_res = mysqli_close($GLOBALS["___mysqli_ston"]))) ? false : $___mysqli_res);
}

?>

1、尝试修改密码为222，修改成功，得到链接

http://dvwa/vulnerabilities/csrf/?password_new=222&password_conf=222&Change=Change#

2、打开新的标签页，使用上面的地址，出现错误提示，密码修改错误

3、打开计算机代理，修改电脑代理服务器IP设置为127.0.0.1，端口设置为8888，BurpSuite调整代理参数与电脑代理一致

4、正常修改密码的网页，使用BurpSuitePro捕获流量包，发现多出Referer属性信息

5、而直接粘贴链接修改密码失败的报文缺少Referer属性信息，右键选择Send to Repeater

5、打开Repeater选项卡，给Request请求中添加Referer信息，Referer需要包括"dvwa"字段（需要符合同源策略），点击Send发送，修改密码成功

DVWA High 级别 CSRF

0、分析网页源代码（路径："D:\phpstudy_pro\DVWA-master\vulnerabilities\csrf\source\high.php"）

<?php

if( isset( $_GET[ 'Change' ] ) ) {
// Check Anti-CSRF token
checkToken( $_REQUEST[ 'user_token' ], $_SESSION[ 'session_token' ], 'index.php' );

// Get input
$pass_new = $_GET[ 'password_new' ];
$pass_conf = $_GET[ 'password_conf' ];

// Do the passwords match?
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 the database
$insert = "UPDATE `users` SET password = '$pass_new' WHERE user = '" . dvwaCurrentUser() . "';";
$result = mysqli_query($GLOBALS["___mysqli_ston"], $insert ) or die( '<pre>' . ((is_object($GLOBALS["___mysqli_ston"])) ? mysqli_error($GLOBALS["___mysqli_ston"]) : (($___mysqli_res = mysqli_connect_error()) ? $___mysqli_res : false)) . '</pre>' );

// Feedback for the user
$html .= "<pre>Password Changed.</pre>";
}
else {
// Issue with passwords matching
$html .= "<pre>Passwords did not match.</pre>";
}

((is_null($___mysqli_res = mysqli_close($GLOBALS["___mysqli_ston"]))) ? false : $___mysqli_res);
}

// Generate Anti-CSRF token
generateSessionToken();

?>

1、正常修改密码并成功，使用BurpSuitePro捕获流量包，发现仍使用get提交方式，但多了验证参数token

2、直接将链接复制粘贴修改密码肯定失败，提示token不正确

有两种方法可以获得token值

方法一：利用DVWA中储存型XSS漏洞获得网页token

1、修改储存型XSS的网页脚本"D:\phpstudy_pro\DVWA-master\vulnerabilities\xss_s\index.php"，加入下面两行代码（修改文件之前做好备份）

<div>Name:test<br/>Message:this is a test comment.<br/></div>
<div>Name:<iframe src='../csrf' onload=alert(frames[0].document.getElementsByName('user_token')[0].value)><br/>Message:1<br/></div>

2、保存文件，打开DVWA High级别下的储存型XSS页面，得到token值

3、将得到的token替换，BurpSuitePro捕获流量包中原有的token

4、发送构造好的数据包，得到响应，密码修改成功

方法二：在BurpSuite安装插件，获取token

1、安装CSRF Token Tracker插件

2、添加一条CSRF Token Tracker规则并勾选，再勾选"根据规则同步requests"

3、截获修改密码请求包

4、将抓到的包Send to Repeater，在Repeater页面修改"password_new"和"password_conf"参数，Send后发现token值发生变化，修改密码成功

DVWA Impossible 级别 CSRF

0、分析网页源代码

<?php

if( isset( $_GET[ 'Change' ] ) ) {
// Check Anti-CSRF token
checkToken( $_REQUEST[ 'user_token' ], $_SESSION[ 'session_token' ], 'index.php' );

// Get input
$pass_curr = $_GET[ 'password_current' ];
$pass_new = $_GET[ 'password_new' ];
$pass_conf = $_GET[ 'password_conf' ];

// Sanitise current password input
$pass_curr = stripslashes( $pass_curr );
$pass_curr = ((isset($GLOBALS["___mysqli_ston"]) && is_object($GLOBALS["___mysqli_ston"])) ? mysqli_real_escape_string($GLOBALS["___mysqli_ston"], $pass_curr ) : ((trigger_error("[MySQLConverterToo] Fix the mysql_escape_string() call! This code does not work.", E_USER_ERROR)) ? "" : ""));
$pass_curr = md5( $pass_curr );

// Check that the current password is correct
$data = $db->prepare( 'SELECT password FROM users WHERE user = (:user) AND password = (:password) LIMIT 1;' );
$data->bindParam( ':user', dvwaCurrentUser(), PDO::PARAM_STR );
$data->bindParam( ':password', $pass_curr, PDO::PARAM_STR );
$data->execute();

// Do both new passwords match and does the current password match the user?
if( ( $pass_new == $pass_conf ) && ( $data->rowCount() == 1 ) ) {
// It does!
$pass_new = stripslashes( $pass_new );
$pass_new = ((isset($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 with new password
$data = $db->prepare( 'UPDATE users SET password = (:password) WHERE user = (:user);' );
$data->bindParam( ':password', $pass_new, PDO::PARAM_STR );
$data->bindParam( ':user', dvwaCurrentUser(), PDO::PARAM_STR );
$data->execute();

// Feedback for the user
$html .= "<pre>Password Changed.</pre>";
}
else {
// Issue with passwords matching
$html .= "<pre>Passwords did not match or current password incorrect.</pre>";
}
}

// Generate Anti-CSRF token
generateSessionToken();

?>