How to remediate – WP Smart Security Plugin for WordPress PHP Object Injection

1. Introduction

The WP Smart Security Plugin for WordPress PHP Object Injection vulnerability affects web servers running a susceptible version of this plugin. This allows an attacker to potentially execute code on your server without needing valid credentials. This impacts the confidentiality, integrity and availability of your website and any associated data. It typically affects websites using the vulnerable plugin.

2. Technical Explanation

The WP Smart Security Plugin for WordPress is vulnerable due to improper handling of PHP objects. An unauthenticated attacker can inject malicious PHP code through this vulnerability, leading to arbitrary code execution on the server. The plugin is no longer actively maintained, meaning security flaws are unlikely to be addressed.

• Exploit mechanism: An attacker sends a crafted request containing a malicious PHP object to the server. This object is then deserialized and executed, allowing for code execution.
• Scope: All versions of the WP Smart Security Plugin for WordPress are affected due to lack of maintenance.

3. Detection and Assessment

You can confirm if a system is vulnerable by checking the installed plugin version and verifying it’s the WP Smart Security Plugin. A thorough method involves reviewing the plugin’s code (if possible) for insecure deserialization practices.

• Quick checks: Check your WordPress plugins list in the admin interface to see if “WP Smart Security” is present.
• Scanning: Nessus vulnerability scan ID 16837 may identify this issue, but relies on self-reported version numbers.
• Logs and evidence: Look for errors related to PHP object deserialization within your WordPress error logs (typically located in /wp-content/debug.log).

wp plugin list | grep "WP Smart Security"

4. Solution / Remediation Steps

The recommended solution is to disable and remove the vulnerable plugin immediately. This is the most effective way to mitigate the risk.

4.1 Preparation

• Take a full backup of your WordPress website, including database and files. Consider taking a snapshot if using virtualised infrastructure.
• No services need to be stopped for this process.
• Roll back plan: Re-install the plugin from the WordPress repository if needed (though strongly discouraged).

4.2 Implementation

1. Step 1: Log in to your WordPress admin interface.
2. Step 2: Navigate to Plugins > Installed Plugins.
3. Step 3: Locate “WP Smart Security” in the list of plugins.
4. Step 4: Click “Deactivate” next to the plugin name.
5. Step 5: Click “Delete” next to the deactivated plugin name. Confirm deletion when prompted.

4.3 Config or Code Example

Before

// Plugin is active in WordPress admin interface

After

// Plugin is no longer listed in WordPress admin interface. It has been deleted.

4.4 Security Practices Relevant to This Vulnerability

Several security practices can help prevent this type of issue. Keeping software up-to-date and using only actively maintained plugins are crucial steps. Least privilege helps limit the impact if a vulnerability is exploited.

• Practice 1: Patch cadence – Regularly update all WordPress core files, themes, and plugins to benefit from security fixes.
• Practice 2: Plugin selection – Only use plugins that are actively maintained by their developers.

4.5 Automation (Optional)

# Example Bash script to disable plugin via WP-CLI (use with caution)
# wp plugin deactivate wp-smart-security --path /path/to/wordpress
# wp plugin delete wp-smart-security --path /path/to/wordpress

5. Verification / Validation

Confirm the fix by verifying that the plugin is no longer installed and active in your WordPress admin interface. Re-run a vulnerability scan to confirm it’s no longer detected. Check key website functionality to ensure it hasn’t been impacted.

• Post-fix check: Navigate to Plugins > Installed Plugins and verify “WP Smart Security” is not present.
• Re-test: Run the `wp plugin list | grep “WP Smart Security”` command again, which should return no results.
• Smoke test: Test basic website functionality such as page loading, form submissions, and user logins to ensure they are working correctly.
• Monitoring: Monitor WordPress error logs for any new errors that may indicate a regression caused by the plugin removal.

wp plugin list | grep "WP Smart Security"

6. Preventive Measures and Monitoring

Update your security baseline to include only actively maintained plugins. Implement checks in your CI/CD pipeline to scan for vulnerable plugins during deployment, for example using a WordPress vulnerability scanner. A regular patch review cycle is also sensible.

• Baselines: Update your WordPress plugin policy to require the use of actively maintained plugins only.
• Asset and patch process: Review all installed plugins at least quarterly for updates and vulnerabilities.

7. Risks, Side Effects, and Roll Back

Removing the plugin may disable any features it provided. Ensure you have alternative solutions in place if needed. The roll back steps involve re-installing the plugin from the WordPress repository (though this is not recommended).

• Risk or side effect 1: Loss of functionality previously provided by the WP Smart Security Plugin.
• Risk or side effect 2: Potential compatibility issues with other plugins if the removed plugin had dependencies.
• Roll back:
  1. Step 1: Navigate to Plugins > Add New in your WordPress admin interface.
  2. Step 2: Search for “WP Smart Security”.
  3. Step 3: Click “Install Now” and then “Activate”.

8. References and Resources

• Vendor advisory or bulletin: https://wordpress.org/plugins/wp-smart-security/
• NVD or CVE entry: Not available, as this is a known issue with an unmaintained plugin.
• Product or platform documentation relevant to the fix: http://www.nessus.org/u?7ea01d3a