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php反序列化长度变化尾部字符串逃逸(0CTF-2016-piapiapia)_php实例_

2023-05-25 428人已围观

简介 php反序列化长度变化尾部字符串逃逸(0CTF-2016-piapiapia)_php实例_

一个很可爱的登录界面:

在这里插入图片描述

进行一下目录扫描,发现源码泄露www.zip,把源码给出:

index.php

 16) die('Invalid user name'); if(strlen($password) < 3 or strlen($password) > 16) die('Invalid password'); if($user->login($username, $password)) { $_SESSION['username'] = $username; header('Location: profile.php'); exit; } else { die('Invalid user name or password'); } } else { ?>Login

Login

在输入账号密码之后进入了profile.php,下面是profile.php的源码:

show_profile($username); if($profile == null) { header('Location: update.php'); } else { $profile = unserialize($profile); $phone = $profile['phone']; $email = $profile['email']; $nickname = $profile['nickname']; $photo = base64_encode(file_get_contents($profile['photo'])); ?>Profile

Hi

还有注册页面的源码(没有太大用),register.php:

 16) die('Invalid user name'); if(strlen($password) < 3 or strlen($password) > 16) die('Invalid password'); if(!$user->is_exists($username)) { $user->register($username, $password); echo 'Register OK!Please Login'; } else { die('User name Already Exists'); } } else { ?>Login

Register

然后是update.php:

 10) die('Invalid nickname'); $file = $_FILES['photo']; if($file['size'] < 5 or $file['size'] > 1000000) die('Photo size error'); move_uploaded_file($file['tmp_name'], 'upload/' . md5($file['name'])); $profile['phone'] = $_POST['phone']; $profile['email'] = $_POST['email']; $profile['nickname'] = $_POST['nickname']; $profile['photo'] = 'upload/' . md5($file['name']); $user->update_profile($username, serialize($profile)); echo 'Update Profile Success!Your Profile'; } else { ?>UPDATE

Please Update Your Profile

核心的处理代码,class.php:

table, $where); } public function register($username, $password) { $username = parent::filter($username); $password = parent::filter($password); $key_list = Array('username', 'password'); $value_list = Array($username, md5($password)); return parent::insert($this->table, $key_list, $value_list); } public function login($username, $password) { $username = parent::filter($username); $password = parent::filter($password); $where = "username = '$username'"; $object = parent::select($this->table, $where); if ($object && $object->password === md5($password)) { return true; } else { return false; } } public function show_profile($username) { $username = parent::filter($username); $where = "username = '$username'"; $object = parent::select($this->table, $where); return $object->profile; } public function update_profile($username, $new_profile) { $username = parent::filter($username); $new_profile = parent::filter($new_profile); $where = "username = '$username'"; return parent::update($this->table, 'profile', $new_profile, $where); } public function __tostring() { return __class__; } } class mysql { private $link = null; public function connect($config) { $this->link = mysql_connect( $config['hostname'], $config['username'], $config['password'] ); mysql_select_db($config['database']); mysql_query("SET sql_mode='strict_all_tables'"); return $this->link; } public function select($table, $where, $ret = '*') { $sql = "SELECT $ret FROM $table WHERE $where"; $result = mysql_query($sql, $this->link); return mysql_fetch_object($result); } public function insert($table, $key_list, $value_list) { $key = implode(',', $key_list); $value = '\'' . implode('\',\'', $value_list) . '\''; $sql = "INSERT INTO $table ($key) VALUES ($value)"; return mysql_query($sql); } public function update($table, $key, $value, $where) { $sql = "UPDATE $table SET $key = '$value' WHERE $where"; return mysql_query($sql); } public function filter($string) { $escape = array('\'', '\\\\'); $escape = '/' . implode('|', $escape) . '/'; $string = preg_replace($escape, '_', $string); $safe = array('select', 'insert', 'update', 'delete', 'where'); $safe = '/' . implode('|', $safe) . '/i'; return preg_replace($safe, 'hacker', $string); } public function __tostring() { return __class__; } } session_start(); $user = new user(); $user->connect($config);

最后是config.php:

看来flag就是在config.php中了,要想办法拿到config.php的内容了。

然后就是代码审计了。

seay代码审计系统也可以给点线索的:

在这里插入图片描述

这个地方貌似有个文件读取的地方,在profile.php中:

 else { $profile = unserialize($profile); $phone = $profile['phone']; $email = $profile['email']; $nickname = $profile['nickname']; $photo = base64_encode(file_get_contents($profile['photo'])); ?>

上面还有个反序列化unserialize,感觉有戏,如果$profile[‘photo']是config.php就可以读取到了,可以对photo进行操作的地方在update.php,有phone、email、nickname和photo这几个

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