CVE-2023-4561: Cross-Site Scripting (XSS) Vulnerability in Omeka-S GitHub Repository Prior to 4..4

A stored Cross-Site Scripting (XSS) vulnerability (designated as CVE-2023-4561) has been discovered in the Omeka-S open-source web publishing platform for sharing digital collections and creating media-rich online exhibits. This vulnerability affects all versions of Omeka-S prior to 4..4. The issue is present within the GitHub repository omeka/omeka-s and allows attackers to embed arbitrary JavaScript code within the application, leading to a range of attacks such as redirection to malicious websites, stealing session cookies, or bypassing access controls.

This blog post aims to provide an in-depth analysis of this vulnerability, including details of the affected code, how an exploit could be crafted, and links to original references. By discussing these details, we hope to raise awareness about the risks associated with this vulnerability and provide a starting point for developers and administrators to mitigate this issue in their applications.

Affected Code and Explanation

The vulnerability resides in a particular code section in the Omeka-S application where user input is not properly sanitized before being displayed on the page. The problematic code snippet can be found in the following file:

omeka-s/application/src/Form/Element/ResourceClassSelect.php

The vulnerable code looks like this

public function getSelectOptions()
{
    $api = $this->getApiManager();
    $response = $api->search('resource_classes', []);
    $options = [];
    foreach ($response->getContent() as $resourceClass) {
        $label = $resourceClass->label();
        $term = $resourceClass->term();
        $options[$label][] = [
            'value' => $term,
            'label' => $term,
        ];
    }
    return $options;
}

In this code snippet, resource class labels and terms are directly rendered on the webpage without proper escape sequences or encoding, allowing an attacker to inject malicious JavaScript code that would execute upon loading the affected page. For instance, a malicious user could create a resource with a label containing the following payload:

<script>alert('XSS')</script>

This payload would set off an alert window on any client's browser when the page containing this resource is loaded, indicating a successful XSS attack.

Exploit Details

To exploit this vulnerability, an attacker would need to create a malicious resource containing a JavaScript payload in its label. They would then have to make sure a victim visits the page containing this malicious resource, which would execute the attacker's JavaScript code.

Bypass access controls

This exploit presents a serious threat to Omeka-S users, as it could potentially compromise user accounts, expose sensitive information, or damage the reputation of the application.

Mitigation and References

To mitigate this vulnerability, it is crucial to upgrade the Omeka-S application to version 4..4 or newer, which has addressed this issue. The fixed version of the application can be found at the following link:

- Omeka-S Releases on GitHub

For more information on the vulnerability and its underlying issue, the following references provide useful insights:

- CVE-2023-4561 from the CVE List
- Omeka-S Security Advisory
- Omeka-S GitHub Repository

Conclusion

In this blog post, we have provided an analysis of the stored XSS vulnerability in Omeka-S, which affects the platform's versions prior to 4..4. Given the potential consequences of this vulnerability, we urge everyone who uses Omeka-S to upgrade to a patched version to avoid falling victim to a cross-site scripting attack. By raising awareness about this issue, we aim to contribute to a safer online environment where both developers and end users can enjoy the benefits of open-source applications without fear of compromise.

Timeline

Published on: 08/28/2023 01:15:00 UTC
Last modified on: 08/29/2023 16:25:00 UTC