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SQL Injection in WordPress websites and how to prevent them

September 9, 2021
Admir Dizdar

What is SQL Injection in WordPress?

One of the most popular open-source Content Management Systems (CMS) is WordPress. WordPress runs millions of websites with an estimated 60% market share.

SQL injection in WordPress is ranked as the second most critical vulnerability, posing a severe risk for website owners. Your WordPress website should be secure from SQL injection if the WordPress core files are up-to-date, but there is something that changes that narrative – third-party plugins and themes.

Here is a list of the most prone types of WordPress plugins:

  1. Subscription pop-ups
  2. Login/Signup forms
  3. E-commerce checkout pages/carts
  4. Search bars
  5. Contact forms
  6. Feedback forms
  7. Generic contact forms
  8. Blog comment forms
  9. Search parameters.

In this article:

How does SQL Injection work in WordPress?

To understand how SQL Injection works in WordPress, let’s quickly have a look at what happens inside a WordPress database.

How does the WordPress Database Work?

Each WordPress website has a database, with the default database management system (DBMS) being MySQL. To retrieve data from a database and generate content for the frontend, WordPress uses SQL queries. Developers working on a WordPress website use PHP and these queries to view, add, retrieve, change or delete code inside the database. You can use WordPress or the control panel to access that database, but you can also make contact with the database using other methods.

Learn more about SQL Injection in PHP web applications.

How Hackers Breach a WordPress Database?

Your application can be vulnerable to SQL injection attacks anywhere your website has a form element (generic contact forms, login portals, blog comment forms, eCommerce checkout pages and search bars amongst others).

One vulnerable form element can open up the entire database to attackers.  The database captures each entry made on a WordPress website, and all the hackers have to do is enter malicious SQL commands instead of valid form entries.

For example, your WordPress website may have a form with an input field asking for a phone number. In an ideal scenario, you would configure that field to accept only numerical entries that follow the structure of phone numbers. But what if you haven’t performed this validation or the plugin you used isn’t working properly? An attacker could enter anything they want into that plain text field – including malicious SQL statements to retrieve data or to initiate a DoS attack.

How to prevent SQL injection in WordPress?

Considering the impact an SQL injection attack can have on your website and the business overall, becoming the victim of a WordPress SQL injection attack can be a sobering thought.

Here is a list of 10 steps you can take to ensure you are as secure as possible:

1. Use Input Validation and Filter User Data

One of the easiest ways to infiltrate a website with SQL injection attacks is through user-submitted data. It is therefore crucial that you use input validation and filtering for user-submitted data to block dangerous character injections. With proper input validation in place, you will test any data that a user submits, making it possible to filter that data and prevent an SQL injection.

2. Avoid Dynamic SQL

To keep your WordPress website safe, use prepared statements, parameterized queries or stored procedures instead of Dynamic SQL. Due to the way Dynamic SQL is automated it creates openings for hackers.

3. Update and Patch Regularly

If you don’t have the latest version of WordPress, along with plugins and themes you are using, you open yourself to security gaps that hackers can exploit. Always make sure you use the latest version of WordPress and that there are no outdated plugins and themes on your website.

4. Use a Firewall

One effective way to keep your WordPress website secure is to set up a firewall. A firewall is a network security system that monitors and controls data coming into your website and acts as an additional layer of security against SQL injection attacks.

5. Remove Unnecessary Database Functionality

More functionality also comes with more security risks. To keep your database protected, consider normalizing it to remove extraneous content and make your website safer.

6. Limit Access Privileges

Inappropriate access privileges can quickly expose your WordPress website to SQL injection attacks.

To keep your website secure, configure your WordPress User Roles and limit what others can access and alter. Ensure that all past users have been removed from editor or contributor roles, and eliminate those potential vulnerabilities.

7. Encrypt Confidential Data

Security is an ongoing process and a never-ending chase between the bad guys and you trying to keep your website secure. So, no matter how secure you consider your website and the database to be, always try to make it safer. By encrypting confidential data in your database, you’re securing it and protecting that data from an SQL injection attack.

8. Don’t Share Extra Information

Database error messages can carry a great deal of information that is useful for hackers. They can contain details such as authentication credentials, server administrators’ email addresses, and even parts of your internal code.

The less information you share, the safer your WordPress website will be. So, to protect your website, consider creating generic messages for errors on a custom HTML page.

9. Monitor SQL Statements

Monitoring SQL statements between database-connected applications can help you identify vulnerabilities in your WordPress website. Monitoring tools can provide valuable insight into potential database issues.

10. Improve your software

While all the above-mentioned steps will ensure your website is pretty safe, even if your software is up-to-date, you can become a victim to cyber-criminals. As security and patching policies tighten up, attackers are relying more on zero-day exploits. 

A zero-day vulnerability is a security vulnerability discovered by attackers before the vendor has become aware of it. As the vendors are unaware, no patch exists, making the attack likely to succeed.

Luckily, there are automated tools that can help identify zero-day vulnerabilities in your applications before they hit production and you become a victim. Consider using a tool like Bright to scan and test your website before you release it to production.

How Nexploit can help detect SQL Injection in WordPress

Bright helps automate the detection and remediation of many vulnerabilities including SQL Injection, early in the development process.

By shifting DAST scans left, and integrating them into the SDLC, developers and application security professionals can detect vulnerabilities early, and remediate them before they appear in production. Nexploit completes scans in minutes and achieves zero false positives, by automatically validating every vulnerability. This allows developers to adopt the solution and use it throughout the development lifecycle.
Scan your WordPress website or any other web app and prevent SQL injection vulnerabilities – try Bright free.

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