Executive Summary

The Advanced Woo Labels plugin for WordPress, in all versions up to and including 2.37, contains a Remote Code Execution (RCE) vulnerability. This occurs because the plugin uses the PHP function call_user_func_array() with a user-controlled callback and parameters in the get_select_option_values() AJAX handler without enforcing an allowlist of permitted callbacks or verifying user capabilities properly. As a result, authenticated users with Contributor-level access or higher can execute arbitrary PHP functions and operating system commands on the server by manipulating the 'callback' parameter.

Useful 0 Not Useful 0

Impact Analysis

This vulnerability allows attackers with Contributor-level access or above to execute arbitrary PHP code and operating system commands on the server hosting the WordPress site. This can lead to full compromise of the server, including unauthorized data access, data modification, installation of malware, disruption of services, and potential takeover of the entire hosting environment.

Useful 0 Not Useful 0

Compliance Impact

I don't know

Useful 0 Not Useful 0

Detection Guidance

[{'type': 'paragraph', 'content': "This vulnerability involves the Advanced Woo Labels WordPress plugin versions up to 2.37, where an authenticated user with Contributor-level access or higher can exploit the AJAX handler `get_select_option_values()` to execute arbitrary PHP functions or OS commands via the 'callback' parameter."}, {'type': 'paragraph', 'content': "Detection on your system can focus on monitoring or inspecting AJAX requests to the WordPress admin area for suspicious calls to the `awl-getSelectOptionValues` action, especially those containing unusual or unexpected 'callback' parameter values."}, {'type': 'paragraph', 'content': 'Since the plugin uses AJAX actions registered as `wp_ajax_awl-getSelectOptionValues`, you can look for HTTP POST requests to `wp-admin/admin-ajax.php` with the parameter `action=awl-getSelectOptionValues`.'}, {'type': 'paragraph', 'content': 'Suggested commands to detect potential exploitation attempts include:'}, {'type': 'list_item', 'content': "Using web server logs (e.g., Apache or Nginx) to grep for suspicious AJAX calls: `grep 'admin-ajax.php' /var/log/apache2/access.log | grep 'action=awl-getSelectOptionValues'`"}, {'type': 'list_item', 'content': "Monitoring POST data for unusual 'callback' parameter values that do not match expected allowed callbacks."}, {'type': 'list_item', 'content': 'Using WordPress security or logging plugins to audit AJAX requests and user capabilities, focusing on Contributor-level or higher users invoking this AJAX action.'}, {'type': 'paragraph', 'content': 'Note that the plugin attempts to verify user capabilities and sanitize inputs, but the vulnerability arises from lack of an allowlist for callbacks and insufficient capability checks in some versions.'}] [1, 2]

Useful 0 Not Useful 0

Mitigation Strategies

Immediate mitigation steps include:

• Update the Advanced Woo Labels plugin to a version later than 2.37 where this vulnerability is fixed.
• If an update is not immediately possible, restrict access to the WordPress admin area to trusted users only, especially limiting Contributor-level and above users from untrusted sources.
• Implement web application firewall (WAF) rules to block or monitor AJAX requests to `admin-ajax.php` with the `action=awl-getSelectOptionValues` parameter.
• Audit user roles and capabilities to ensure that only trusted users have Contributor-level or higher access.

These steps help prevent exploitation by limiting the ability of attackers to invoke the vulnerable AJAX handler or execute arbitrary callbacks.

Useful 0 Not Useful 0