Recently, a security vulnerability was discovered in the popular WordPress plugin, Contact Form 7, and its addon Live Preview for Contact Form 7. This vulnerability, identified as CVE-2023-47830, exposes an "incorrectly configured access control security level" issue that could potentially allow attackers to exploit the plugin and its addons. In this post, we will provide a detailed analysis of the vulnerability, demonstrate a code snippet, and provide links to the original references and resources.

Vulnerability Details

The vulnerability exists in the Live Preview for Contact Form 7 addon versions ranging from N/A to 1.2.. The issue occurs due to a missing authorization check within the plugin's code, which could allow attackers to bypass the intended access control security level.

Impact

Successfully exploiting this vulnerability could allow attackers to gain unauthorized access to sensitive information and capabilities within the plugin, which may result in data leakage or unauthorized modifications.

Code Snippet

The missing authorization check can be observed in the following code snippet from the vulnerable Live Preview for Contact Form 7 addon.

add_action('wp_ajax_cf7_live_preview', 'cf7_live_preview_callback');
function cf7_live_preview_callback() {
    if (isset($_POST['form_id']) && isset($_POST['config'])) {
        $form = WPCF7_ContactForm::get_instance($_POST['form_id']);

        // Missing authorization check should be here

        if ($form !== NULL) {
            $config = stripslashes_deep(json_decode(stripslashes($_POST['config']), true));
            $form = wpcf7_update_contact_form($form->id(), $config);

            $html = do_shortcode('[contact-form-7 id="' . $form->id() . '"]');
            echo $html;
            die();
        }
    }

    echo 'error';
    die();
}

As seen in the code snippet above, the cf7_live_preview_callback() function takes the form ID and configuration parameters from the POST request, retrieves the specified contact form, and then renders the form with the new configurations. However, there is no authorization check in place to prevent attackers with malicious intent from exploiting this functionality to gain unauthorized access.

Exploit

To exploit this vulnerability, an attacker can send a crafted AJAX request to the WordPress website, as demonstrated in the following example:

curl -X POST "https://targetsite.com/wp-admin/admin-ajax.php"; \
  --data "action=cf7_live_preview&form_id=TARGET_FORM_ID&config=MALICIOUS_CONFIG"

By sending a specially crafted POST request, the attacker can perform unauthorized actions, such as modifying the form configurations or even hijacking the form's data submissions.

Remediation

To mitigate the risk of this vulnerability, it is highly recommended that WordPress website administrators update their Live Preview for Contact Form 7 addon to the latest available version. If the addon is no longer maintained or does not have a patched version available, it is advised to consider using an alternative solution that provides regular security updates.

Additionally, plugin developers should ensure that proper authorization checks are implemented for any sensitive functionality exposed through AJAX endpoints or other means.

References

For more information regarding the CVE-2023-47830 vulnerability, you may refer to the following resources:

- CVE-2023-47830 - Live Preview for Contact Form 7 Missing Authorization Vulnerability
- WordPress Plugin Live Preview for Contact Form 7 Security Advisory

Conclusion

The CVE-2023-47830 vulnerability demonstrates the importance of implementing proper access control and authorization checks within WordPress plugins and their addons. By staying vigilant and keeping your site's plugins up-to-date, you can help protect your website and its users from potential security risks.

Timeline

Published on: 12/09/2024 13:15:31 UTC