Can you explain this vulnerability to me?

The Booking Calendar plugin for WordPress has a vulnerability known as Insecure Direct Object Reference (IDOR) in all versions up to and including 10.14.14. This vulnerability exists in the handle_ajax_save function because it lacks proper validation on a user-controlled key.

As a result, authenticated users with Subscriber-level access or higher, who also have booking permissions granted by an Administrator, can exploit this flaw to modify other users' plugin settings. These settings include booking calendar display options, which can disrupt the booking calendar functionality for the targeted user.

Useful 0 Not Useful 0

How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:

I don't know

Useful 0 Not Useful 0

How can this vulnerability impact me? :

This vulnerability allows attackers with relatively low privileges (Subscriber-level access and booking permissions) to alter other users' plugin settings without authorization.

The impact includes disruption of the booking calendar functionality for targeted users, potentially causing confusion, booking errors, or denial of service in the booking process.

Since the attacker cannot escalate privileges beyond their own but can modify settings of others, this can lead to unauthorized changes that affect user experience and trust in the booking system.

Useful 0 Not Useful 0

How can this vulnerability be detected on my network or system? Can you suggest some commands?

[{'type': 'paragraph', 'content': "This vulnerability involves an authenticated user with Subscriber-level access and booking permissions modifying other users' plugin settings via the handle_ajax_save function. Detection would involve monitoring AJAX requests to the Booking Calendar plugin's save-user-meta endpoint for unauthorized attempts to modify user data."}, {'type': 'paragraph', 'content': 'Specifically, you can look for suspicious POST requests to the AJAX action related to saving user meta data, especially those containing parameters like user_id, data_name, data_value, nonce_action, and nonce.'}, {'type': 'paragraph', 'content': 'Commands to detect such activity might include inspecting web server logs or using tools like curl or wget to simulate or monitor AJAX requests. For example, you could use:'}, {'type': 'list_item', 'content': 'grep or tail commands on your web server access logs to find POST requests to admin-ajax.php with action=AJAX_SAVE_USER_META_DATA'}, {'type': 'list_item', 'content': "Using curl to test the AJAX endpoint with crafted parameters to verify if unauthorized changes are possible (only in a safe testing environment): curl -X POST -d 'action=AJAX_SAVE_USER_META_DATA&user_id=TARGET_USER_ID&data_name=...&data_value=...&nonce_action=...&nonce=...' https://yourwordpresssite.com/wp-admin/admin-ajax.php"}, {'type': 'paragraph', 'content': 'However, no explicit detection commands or signatures are provided in the available resources.'}] [3]

Useful 0 Not Useful 0

What immediate steps should I take to mitigate this vulnerability?

The primary mitigation step is to update the Booking Calendar plugin to version 10.14.15 or later, as this version includes extensive code modifications likely addressing the vulnerability.

Additionally, restrict booking permissions carefully, ensuring only trusted users have booking permissions granted by an Administrator, since the vulnerability requires such permissions.

Monitoring and validating AJAX requests for proper nonce verification and user authorization is also important, but the main fix is applying the plugin update.

Useful 0 Not Useful 0