CVE-2022-3334 - Easy WP SMTP WordPress Plugin Unserialization Vulnerability Leading to PHP Object Injection

A critical vulnerability (CVE-2022-3334) has recently been discovered in the Easy WP SMTP WordPress plugin, which affects versions prior to 1.5.. This vulnerability allows an attacker to perform a PHP object injection attack if a site administrator imports a malicious file and an appropriate gadget chain is present on the WordPress site. In this post, we will dive into the details of the vulnerability, examine a code snippet that illustrates the issue, and provide links to additional references and resources.

Vulnerability Details

The vulnerability discovered in the Easy WP SMTP WordPress plugin is primarily due to the insecure unserialization of imported files. The plugin deserializes the contents of an imported file, leaving open the possibility for a PHP object injection attack. The actual attack would only be successful if a gadget chain was present on the site, providing a pathway for malicious code to be executed.

Here's a code snippet highlighting this issue in the Import() function

public function Import(){
    if (!current_user_can('manage_options')){
        wp_die(__('You do not have sufficient permissions to access this page.', 'easy-wp-smtp'));
    }

    if (isset($_POST['swpsmtp_import_settings']) && check_admin_referer(plugin_basename(__FILE__), 'swpsmtp_nonce_name')){
        if (!empty($_FILES['swpsmtp_import_settings_file']['tmp_name'])){
            if (!function_exists('get_home_path')){
                require_once ABSPATH . 'wp-admin/includes/file.php';
            }

            $filePath = get_home_path() . 'smtp_import_settings.txt';
            $fileContents = file_get_contents($filePath);

            if ($fileContents !== false){
                $importOptions = @unserialize($fileContents);
                if ($importOptions !== false){
                    update_option('swpsmtp_options', $importOptions);
                    echo '<div id="message" class="updated fade"><p>' . __('The settings have been imported successfully.', 'easy-wp-smtp') . '</p></div>';
                } else {
                    echo '<div id="message" class="error"><p>' . __('Error occurred during the import process.', 'easy-wp-smtp') . '</p></div>';
                }
            }
        }
    }

    // Further code ...
}

As we can see in the above code snippet, the $fileContents variable contains the content of an imported file, which was retrieved using the file_get_contents function. The plugin then attempts to unserialize this content using the unserialize function, but offers no validation or sanitization to ensure that the content is safe to unserialize.

Exploitation

To exploit this vulnerability, an attacker would need to convince a site administrator to import a file containing malicious code and have an appropriate gadget chain in place. Once the conditions were met, the attacker would be able to execute malicious PHP code and potentially cause widespread damage to the affected website.

Mitigation

To protect your WordPress site from this vulnerability, it is crucial to update the Easy WP SMTP plugin to version 1.5. or higher. This update resolves the issue by implementing a safer process for importing files and mitigates the potential for PHP object injection attacks.

Additionally, it is essential to stay vigilant against phishing emails, as attackers often attempt to manipulate users into performing actions that benefit the attacker, such as downloading and importing malicious files.

Conclusion

The discovery of CVE-2022-3334 highlights the importance of securely handling user-supplied input and serialization in web applications. Stay informed and up-to-date on the latest vulnerabilities and patches to ensure the security of your website and user data.

Original References and Resources

1. Easy WP SMTP WordPress plugin (update to version 1.5.): https://wordpress.org/plugins/easy-wp-smtp/
2. CVE Details: https://www.cvedetails.com/cve/CVE-2022-3334/
3. Official WordPress plugin repository with change log: https://plugins.trac.wordpress.org/browser/easy-wp-smtp/#trunk

Stay educated on web application security and review resources such as the OWASP Top Ten Project (https://owasp.org/www-project-top-ten/), which provides a comprehensive guide to the most critical security risks in web applications.

Timeline

Published on: 10/31/2022 16:15:00 UTC
Last modified on: 11/01/2022 13:57:00 UTC