Low:
源码:
<?php if( isset( $_GET[ 'Login' ] ) ) { // Get username $user = $_GET[ 'username' ]; // Get password $pass = $_GET[ 'password' ]; $pass = md5( $pass ); // Check the database $query = "SELECT * FROM `users` WHERE user = '$user' AND password = '$pass';"; $result = mysql_query( $query ) or die( '<pre>' . mysql_error() . '</pre>' ); if( $result && mysql_num_rows( $result ) == 1 ) { // Get users details $avatar = mysql_result( $result, 0, "avatar" ); // Login successful echo "<p>Welcome to the password protected area {$user}</p>"; echo "<img src=\"{$avatar}\" />"; } else { // Login failed echo "<pre><br />Username and/or password incorrect.</pre>"; } mysql_close(); } ?>
没有任何防爆破机制,还有SQL注入漏洞
直接burpsuite爆破密码
Medium:
源码:
<?php if( isset( $_GET[ 'Login' ] ) ) { // Sanitise username input $user = $_GET[ 'username' ]; $user = mysql_real_escape_string( $user ); // Sanitise password input $pass = $_GET[ 'password' ]; $pass = mysql_real_escape_string( $pass ); $pass = md5( $pass ); // Check the database $query = "SELECT * FROM `users` WHERE user = '$user' AND password = '$pass';"; $result = mysql_query( $query ) or die( '<pre>' . mysql_error() . '</pre>' ); if( $result && mysql_num_rows( $result ) == 1 ) { // Get users details $avatar = mysql_result( $result, 0, "avatar" ); // Login successful echo "<p>Welcome to the password protected area {$user}</p>"; echo "<img src=\"{$avatar}\" />"; } else { // Login failed sleep( 2 ); echo "<pre><br />Username and/or password incorrect.</pre>"; } mysql_close(); } ?>
加了mysql_real_escape_string()过滤了一些特殊字符,基本防止了SQL注入,但是还是可以爆破,只不过加了sleep(2)就慢一点而已。
High:
源码:
<?php if( isset( $_GET[ 'Login' ] ) ) { // Check Anti-CSRF token checkToken( $_REQUEST[ 'user_token' ], $_SESSION[ 'session_token' ], 'index.php' ); // Sanitise username input $user = $_GET[ 'username' ]; $user = stripslashes( $user ); $user = mysql_real_escape_string( $user ); // Sanitise password input $pass = $_GET[ 'password' ]; $pass = stripslashes( $pass ); $pass = mysql_real_escape_string( $pass ); $pass = md5( $pass ); // Check database $query = "SELECT * FROM `users` WHERE user = '$user' AND password = '$pass';"; $result = mysql_query( $query ) or die( '<pre>' . mysql_error() . '</pre>' ); if( $result && mysql_num_rows( $result ) == 1 ) { // Get users details $avatar = mysql_result( $result, 0, "avatar" ); // Login successful echo "<p>Welcome to the password protected area {$user}</p>"; echo "<img src=\"{$avatar}\" />"; } else { // Login failed sleep( rand( 0, 3 ) ); echo "<pre><br />Username and/or password incorrect.</pre>"; } mysql_close(); } // Generate Anti-CSRF token generateSessionToken(); ?>
加入了stripslashes()去除反斜线,还加入了Anti-CSRFtoken防CSRF和爆破。
这里就说下思路吧:
写个python脚本,先获取服务端传来的token值,再用此token值去爆破密码,失败则再获取一次新的token再破解,直至成功。可以通过判断成功和失败页面返回的字符来判断是否成功,也可以像burpsuite一样看返回页面长度来判断是否成功。
Impossible:
源码:
<?php if( isset( $_POST[ 'Login' ] ) ) { // Check Anti-CSRF token checkToken( $_REQUEST[ 'user_token' ], $_SESSION[ 'session_token' ], 'index.php' ); // Sanitise username input $user = $_POST[ 'username' ]; $user = stripslashes( $user ); $user = mysql_real_escape_string( $user ); // Sanitise password input $pass = $_POST[ 'password' ]; $pass = stripslashes( $pass ); $pass = mysql_real_escape_string( $pass ); $pass = md5( $pass ); // Default values $total_failed_login = 3; $lockout_time = 15; $account_locked = false; // Check the database (Check user information) $data = $db->prepare( 'SELECT failed_login, last_login FROM users WHERE user = (:user) LIMIT 1;' ); $data->bindParam( ':user', $user, PDO::PARAM_STR ); $data->execute(); $row = $data->fetch(); // Check to see if the user has been locked out. if( ( $data->rowCount() == 1 ) && ( $row[ 'failed_login' ] >= $total_failed_login ) ) { // User locked out. Note, using this method would allow for user enumeration! //echo "<pre><br />This account has been locked due to too many incorrect logins.</pre>"; // Calculate when the user would be allowed to login again $last_login = $row[ 'last_login' ]; $last_login = strtotime( $last_login ); $timeout = strtotime( "{$last_login} +{$lockout_time} minutes" ); $timenow = strtotime( "now" ); // Check to see if enough time has passed, if it hasn't locked the account if( $timenow > $timeout ) $account_locked = true; } // Check the database (if username matches the password) $data = $db->prepare( 'SELECT * FROM users WHERE user = (:user) AND password = (:password) LIMIT 1;' ); $data->bindParam( ':user', $user, PDO::PARAM_STR); $data->bindParam( ':password', $pass, PDO::PARAM_STR ); $data->execute(); $row = $data->fetch(); // If its a valid login... if( ( $data->rowCount() == 1 ) && ( $account_locked == false ) ) { // Get users details $avatar = $row[ 'avatar' ]; $failed_login = $row[ 'failed_login' ]; $last_login = $row[ 'last_login' ]; // Login successful echo "<p>Welcome to the password protected area <em>{$user}</em></p>"; echo "<img src=\"{$avatar}\" />"; // Had the account been locked out since last login? if( $failed_login >= $total_failed_login ) { echo "<p><em>Warning</em>: Someone might of been brute forcing your account.</p>"; echo "<p>Number of login attempts: <em>{$failed_login}</em>.<br />Last login attempt was at: <em>${last_login}</em>.</p>"; } // Reset bad login count $data = $db->prepare( 'UPDATE users SET failed_login = "0" WHERE user = (:user) LIMIT 1;' ); $data->bindParam( ':user', $user, PDO::PARAM_STR ); $data->execute(); } else { // Login failed sleep( rand( 2, 4 ) ); // Give the user some feedback echo "<pre><br />Username and/or password incorrect.<br /><br/>Alternative, the account has been locked because of too many failed logins.<br />If this is the case, <em>please try again in {$lockout_time} minutes</em>.</pre>"; // Update bad login count $data = $db->prepare( 'UPDATE users SET failed_login = (failed_login + 1) WHERE user = (:user) LIMIT 1;' ); $data->bindParam( ':user', $user, PDO::PARAM_STR ); $data->execute(); } // Set the last login time $data = $db->prepare( 'UPDATE users SET last_login = now() WHERE user = (:user) LIMIT 1;' ); $data->bindParam( ':user', $user, PDO::PARAM_STR ); $data->execute(); } // Generate Anti-CSRF token generateSessionToken(); ?>
爆破到3次失败就锁定帐号,要等15分钟,有效防止爆破,pdo进一步防止SQL注入,基本无解。