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0x00 前言

源码下载链接

日常刷题 给了一个蝉知cms hint:后台密码五位 没扫 凭经验试了几个 后台 /admin.php admin 12345

0x01 brain.md

一开始想的就是基础文件上传getshell 一些上传logo的地方都被ban了 在设计模块中可以自定义网站头部的php源代码 通过在服务器创建文件判断管理员身份 在组件素材库处可以上传txt文件 拦一下包看看

POST /chanzhi/www/admin.php?m=file&f=editsource&fileID=1 HTTP/1.1
Host: 192.168.2.26
Content-Length: 290
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
Origin: http://192.168.2.26
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryNMMMY8BhfGvBoBai
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.102 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Referer: http://192.168.2.26/chanzhi/www/admin.php?m=file&f=browsesource
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9,zh-CN;q=0.8,zh;q=0.7
Cookie: adminsid=pvbj0olrrghhe6tmmgq7r8vspl; adminLang=zh-cn; adminDevice=desktop; theme=default; currentGroup=design
Connection: close

------WebKitFormBoundaryNMMMY8BhfGvBoBai
Content-Disposition: form-data; name="filename"

wipqq
------WebKitFormBoundaryNMMMY8BhfGvBoBai
Content-Disposition: form-data; name="upFile"; filename=""
Content-Type: application/octet-stream


------WebKitFormBoundaryNMMMY8BhfGvBoBai--

源码跟进到函数 D:\phpStudy\PHPTutorial\WWW\chanzhi\system\module\file\control.php

public function editSource($fileID)
    {
        $this->file->setSavePath('source');
        $file = $this->file->getById($fileID);
        if(!empty($_POST))
        {
            if(!$this->file->checkSavePath()) $this->send(array('result' => 'fail', 'message' => $this->lang->file->errorUnwritable));
            if($this->post->filename == false or $this->post->filename == '') $this->send(array('result' => 'fail', 'message' => $this->lang->file->nameEmpty));

            $filename = $this->post->filename;
            if(!validater::checkFileName($filename)) $this->send(array('result' => 'fail', 'message' => $this->lang->file->evilChar));

            if(!$this->post->continue)
            {
                $extension    = $this->file->getExtension($_FILES['upFile']['name']);
                $sameUpFile   = $this->file->checkSameFile(str_replace('.' . $extension, '', $_FILES['upFile']['name']), $fileID);
                $sameFilename = $this->file->checkSameFile($this->post->filename, $fileID);
                if(!empty($sameUpFile) or !empty($sameFilename))$this->send(array('result' => 'fail', 'message' => $this->lang->file->sameName));
            }

            $result = $this->file->editSource($file, $filename);
            if($result) $this->send(array('result' => 'success','message' => $this->lang->saveSuccess, 'locate' => $this->createLink('file', 'browseSource')));
            $this->send(array('result' => 'fail', 'message' => dao::getError() ));
        }
        $this->view->title      = $this->lang->file->edit;
        $this->view->modalWidth = 500;
        $this->view->file       = $file;
        $this->display();
    }

跟进checkfilename D:\phpStudy\PHPTutorial\WWW\chanzhi\system\lib\base\filter\filter.class.php 没有过滤 /

public static function checkFileName($var)
    {
        return !preg_match('/>+|:+|<+/', $var);
    }

跟进$this->file->editSource D:\phpStudy\PHPTutorial\WWW\chanzhi\system\module\file\model.php

public function editSource($file, $fileName)
    {
        $files = $this->getUpload('upFile', $file->objectType);
        $uploadPath = $this->app->getDataRoot();
        if(!empty($files))
        {
            /* Use post fileName as file title. */
            $_FILES['upFile']['name'] = $fileName . '.' . $file->extension;

            $replaceResult = $this->replaceFile($file->id, 'upFile');
            if(!$replaceResult) return false;
        }

        if($fileName != $file->title) 
        {
            $file = $this->getByID($file->id);
            if(!file_exists($file->realPath)) return false;
            $newPath = dirname($file->realPath) . DS . $fileName . '.' . $file->extension;
            $result = copy($file->realPath, $newPath);
            if(!$result) return false;
            @unlink($file->realPath);
            
            $newPathname = str_replace($uploadPath, '', $newPath);
            $this->dao->update(TABLE_FILE)->set('title')->eq($fileName)->set('pathName')->eq($newPathname)->where('id')->eq($file->id)->exec();
        }

        return !dao::isError();
    }

最后的newPath只是做了简易的拼接 存在目录穿越 web端的存储路径只是相对路径 所以还是得把源码包down下来仔细看一下 /var/www/html/www/data/source/default/blank/ 目标目录 /var/www/html/system/tmp/

0x02 rethink

水平不济 看源码时可能纰漏很多