CVE-2024-25737 - Uncovering SSRF Vulnerability in Open Library Foundation VuFind: A Detailed Analysis and Exploitation Guide

Open Library Foundation VuFind, a popular open-source library management software, has been reported to have a critical Server-Side Request Forgery (SSRF) vulnerability in versions 2.4 through 9.1 before 9.1.1. This vulnerability, cataloged as CVE-2024-25737, has the potential to enable remote attackers to access internal HTTP servers and execute Cross-Site Scripting (XSS) attacks via the proxy GET parameter. In this long-read post, we will dive into the technical details of this vulnerability, examine a code snippet from the vulnerable component, and explore the exploit process step by step.

Vulnerable Component

The SSRF vulnerability was found in the /Cover/Show route, specifically in the showAction function inside the CoverController.php file. The vulnerable component allows users to make proxy requests, effectively forwarding arbitrary URLs via the proxy GET parameter. This oversight can be exploited by an attacker to access internal HTTP servers and perform XSS attacks.

Below is a simplified code snippet from the vulnerable showAction function in CoverController.php

public function showAction()
{
    // Retrieving user input from the proxy GET parameter
    $proxyUrl = $this->params()->fromQuery('proxy');

    if (!empty($proxyUrl))
    {
      // Fetching the content from the provided URL and returning as response
      $response = $this->httpGet($proxyUrl);
      return $this->createResponse($response->getBody());
    }
}

Exploit Details

To exploit this vulnerability, an attacker can craft a malicious URL containing an arbitrary URL as the proxy GET parameter. By doing this, they can force the application to make requests to internal HTTP servers, bypassing any network restrictions or firewalls that might be in place.

For example, consider an attacker wants to access an internal HTTP server with the IP address "192.168.1.1", hosting a vulnerable application on port 800. They can craft the following malicious URL:

http://vufind.example.com/Cover/Show?proxy=http://192.168.1.1:800/vulnerable_app

Upon opening this URL, the vulnerable application will fetch and display the contents of the specified internal HTTP server. Consequently, this capability can be further exploited to perform XSS attacks – a tactic commonly employed by hackers to inject malicious scripts into webpages, thereby allowing them to steal sensitive information, impersonate users and perform various destructive actions on the victim's behalf.

To learn more about the CVE-2024-25737 vulnerability and understand its implications

- National Vulnerability Database (NVD): CVE-2024-25737
- Open Library Foundation VuFind: Release Notes for Version 9.1.1

Mitigation

To mitigate this SSRF vulnerability, system administrators are urged to upgrade their VuFind installation to the latest version, 9.1.1, as this issue has already been addressed in the update. Additionally, application developers should avoid implementing proxy features without proper input validation and output escaping.

In this long-read post, we have uncovered the SSRF vulnerability (CVE-2024-25737) in Open Library Foundation VuFind, explored the relevant code snippet in the CoverController.php file, and delved into the exploit process. Those responsible for maintaining the affected software are urged to take immediate action to rectify the vulnerability, safeguarding their systems from potential attacks in the process.

Timeline

Published on: 05/22/2024 19:15:08 UTC
Last modified on: 11/12/2024 19:35:06 UTC