Arbitrary Post Deletion in Abandoned Contact Form 7 WordPress Plugin

Executive Summary

The Abandoned Contact Form 7 plugin for WordPress has a vulnerability in versions up to and including 2.2 that allows unauthorized arbitrary post deletion. This happens because the function action__remove_abandoned() lacks proper capability checks and nonce validation. It accepts a user-supplied recover_id parameter from a POST request and passes it directly to the wp_delete_post() function with the force-delete flag enabled, without verifying if the post ID belongs to the plugin's own post type. As a result, unauthenticated attackers can permanently delete any posts, pages, or other content on the affected WordPress site by sending a single specially crafted admin-ajax request.

Useful 0 Not Useful 0

Impact Analysis

This vulnerability can lead to permanent deletion of arbitrary posts, pages, or other content on a WordPress site using the affected plugin. Since the deletion can be performed by unauthenticated attackers, it poses a significant risk of data loss and content disruption. The integrity and availability of website content can be compromised, potentially affecting the site's operation and user trust.

Useful 0 Not Useful 0

Detection Guidance

Detection of this vulnerability involves monitoring for unauthorized POST requests to the admin-ajax.php endpoint with the action parameter set to remove_abandoned.

Specifically, look for POST requests containing the recover_id parameter targeting the wp_ajax_remove_abandoned or wp_ajax_nopriv_remove_abandoned hooks.

You can use network monitoring tools or web server logs to identify such suspicious requests.

Example command to search web server logs for such requests (assuming Apache logs):

• grep 'admin-ajax.php' /var/log/apache2/access.log | grep 'action=remove_abandoned'

Alternatively, use tools like tcpdump or Wireshark to capture and filter HTTP POST requests containing the action=remove_abandoned parameter.

Useful 0 Not Useful 0

Mitigation Strategies

Immediate mitigation steps include updating the Abandoned Contact Form 7 plugin to a version later than 2.2 where this vulnerability is fixed.

If an update is not immediately available, restrict access to admin-ajax.php or disable the vulnerable hooks by applying custom code or security plugins that block unauthorized requests to the remove_abandoned action.

Additionally, implement web application firewall (WAF) rules to block unauthenticated POST requests attempting to invoke the remove_abandoned action.

Regularly back up your WordPress site to recover any content that might be deleted due to exploitation.

Useful 0 Not Useful 0