Code Injection in WordPress Request a Quote Plugin

Executive Summary

The Request a Quote plugin for WordPress versions up to and including 2.5.5 has a code injection vulnerability via the emd_delete_file AJAX action.

This happens because the emd_delete_file() handler takes a PHP function name from an attacker-controlled POST parameter called 'path' and calls it dynamically without proper validation.

The handler is registered for unauthenticated AJAX requests and only protected by a nonce that is publicly available on the quote form page, allowing attackers to invoke arbitrary zero-argument PHP functions on the server.

This can lead to execution of dangerous PHP functions like phpinfo(), which can expose sensitive server information or allow other destructive actions.

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Detection Guidance

Detection of this vulnerability involves monitoring for suspicious AJAX requests to the emd_delete_file action, especially POST requests containing the 'path' parameter that could be used to invoke arbitrary PHP functions.

You can use network monitoring tools or web server logs to look for POST requests to the endpoint handling wp_ajax_nopriv actions related to the Request a Quote plugin.

Example commands to detect such activity might include:

• Using grep on web server logs to find suspicious POST requests: grep "POST.*emd_delete_file" /var/log/apache2/access.log
• Using curl to test if the vulnerable AJAX action is accessible without authentication: curl -X POST -d "action=emd_delete_file&path=phpinfo" https://yourwordpresssite.com/wp-admin/admin-ajax.php
• Using intrusion detection systems or web application firewalls to alert on unusual or unauthorized AJAX calls to emd_delete_file.

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Impact Analysis

This vulnerability allows unauthenticated attackers to execute arbitrary zero-argument PHP functions on the server hosting the vulnerable plugin.

Potential impacts include exposure of sensitive server configuration and credentials if functions like phpinfo() are invoked.

Attackers might also execute other destructive built-in PHP functions, potentially compromising the integrity of the server or application.

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Compliance Impact

The vulnerability allows unauthenticated attackers to execute arbitrary PHP functions on the server, potentially exposing sensitive server configuration and credentials.

Exposure of sensitive information or unauthorized access to server functions could lead to violations of data protection regulations such as GDPR or HIPAA, which require safeguarding personal and sensitive data.

Therefore, this vulnerability may negatively impact compliance with standards that mandate strict controls over data confidentiality and integrity.

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Mitigation Strategies

Immediate mitigation steps include updating the Request a Quote plugin to a version later than 2.5.5 where this vulnerability is fixed.

If an update is not immediately possible, restrict access to the vulnerable AJAX action by implementing additional authentication or disabling the emd_delete_file AJAX handler for unauthenticated users.

Additionally, monitor your logs for suspicious activity and consider applying web application firewall rules to block exploit attempts targeting this vulnerability.

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