Protecting your WordPress website against SQL injection attacks

If you own a WordPress website, then chances are you’ve heard of SQL injections in WordPress. These malicious attacks can wreak havoc on your website and leave it vulnerable to hackers. Fortunately, there are steps you can take to protect your website from the threat of a WordPress SQL injection attack. Let’s explore what is a WordPress SQL injection attack and the best ways to prevent them.

What Is a WordPress SQL Injection Attack (SQLi)?

Cusco, Peru

SQL is short for Structured Query Language — the most widely used language for databases. WordPress uses MySQL, an open-source database. With SQL Injection, an attacker can abuse the input fields by inserting malicious SQL statements that execute SQL commands and can create, retrieve, update, and even delete the data in the database, such as passwords, user data, and credit cards.

This type of attack is particularly dangerous because it exploits the vulnerabilities in a WordPress web application’s code, allowing hackers to access private information that they otherwise wouldn’t be able to get their hands on. It’s possible that an attacker can obtain a persistent backdoor into a company’s systems, leading to a long-term breach that can go unnoticed for months. In some cases, hackers who have gained access to systems via SQL injections will issue ransomware demands.

Vulnerable Points for WordPress SQL Injection Attacks

Generally, attackers gain entry to a SQL database through input fields like customer comments, contact forms, or search bars.

Types of SQL Injection Attacks

  • Subverting application logic. An attacker can change a query to interfere with the application’s logic.
  • Retrieving hidden data. An attacker can modify a SQL query to return additional results.
  • UNION attacks. An attacker can receive data from different database tables.
  • Scoping the database. An attacker can learn valuable information about the version and structure of the database.
  • Blind SQL injection, where the results of a query you control are not returned in the application’s responses. BlindSQL injection enables an attacker to modify the syntax of a SQL query in order to retrieve, corrupt, or delete data. A successful exploit manipulates the query’s logic. Queries created by concatenating strings with SQL syntax and user-supplied data are prone to this vulnerability. When any part of the string concatenation can be modified, an attacker has the ability to change the meaning of the query.

Detecting a WordPress SQL Injection Attack

Wurzeralm, Spital am Pyhrn, Austria

Typical detection techniques for WordPress SQL injection vulnerabilities use a payload that attempts to produce a SQL error from the WordPress web application. Detection based on blind WordPress SQL injection uses inference based on the differences among the application’s responses to various payloads. Blind SQL does not rely on error messages, which is beneficial when testing web applications that trap errors.

A scanning engine can use a technique called True/False inference to determine if there is a blind SQL injection vulnerability in a WordPress website. Basically, it uses two payloads: one with a True condition and another with a False condition. If there is a blind SQL injection vulnerability, the query with the True condition payload will cause the web application to return a different response than the False condition payload.

A good example of a True condition payload is ‘ AND 1=1 (since 1 always equals 1, the condition is true). An example of a False condition payload is ‘ AND 1=2 (since 1 does not equal 2, the condition is false).

A good example of a True condition payload is ‘ AND 1=1 (since 1 always equals 1, the condition is true). An example of a False condition payload is ‘ AND 1=2 (since 1 does not equal 2, the condition is false).

– True condition payload: John’ AND 1=1

This condition is true, so one record is returned, and the output is John, which is the same as if the payload was the name John by itself.

– False condition payload: John’ AND 1=2

The condition is false, so no records are returned, and the output is nothing or a message such as No Results Found.

Seeing the difference in results, the scanning engine draws the conclusion that there is a blind SQL injection vulnerability.

WordPress database-specific factors

Some core features of the SQL language are implemented in the same way across popular database platforms, and so many ways of detecting and exploiting SQL injection vulnerabilities work identically across database structure.

However, there are also many differences between databases. This means that some techniques for detecting and exploiting SQL injection work differently on different platforms.

Impact of WordPress SQL Injection Attacks

Melkbosstrand, Western Cape, South Africa

The scope of a WordPress database SQL injection exploit on a WordPress website varies greatly. If any SQL statement can be injected into the query, then the attacker can execute SQL commands and has the equivalent access of a WordPress database administrator. This access could lead to theft of data, malicious corruption of data, or deletion of data.

Attackers can spoof identity, tamper with existing data, cause issues such as voiding transactions or changing balances, allow the complete disclosure of all data on the system, and destroy the data or make it otherwise unavailable.

Overview of Solutions for WordPress SQL Injection Attack

Seattle, WA, USA

SQL injection vulnerabilities for WordPress sites can be addressed in three areas: input validation, query creation, and database security.

All input received from the client side should be validated for correct content. If a value’s type or content range is known beforehand, then stricter filters should be applied. For example, an email address should be in a specific format and only contain characters that make it a valid address; or numeric fields like a USA zip code should be limited to five-digit values.

Prepared statements (also referred to as parameterized queries) provide strong protection from SQL injection. Prepared statements are precompiled SQL queries whose parameters can be modified when the query is executed. Prepared statements enforce the logic of the query and will fail if the query cannot be compiled correctly. Programming languages that support prepared statements provide specific functions for creating queries. These functions are more secure than string concatenation for assigning user-supplied data to a query.

Stored procedures are precompiled queries that reside in the database. Like prepared statements, they also enforce the separation of query data and logic. SQL statements that call stored procedures should not be created via string concatenation, otherwise, their security benefits are negated.

SQL injection exploits can be mitigated by the use of Access Control Lists or role-based access within the database. For example, a read-only account would prevent an attacker from modifying data, but would not prevent the user from viewing unauthorized data. Table and row-based access controls potentially minimize the scope of a compromise, but they do not prevent exploits.

Examples of WordPress SQL injections

Portet-sur-garonne, France

WPScan and Jetpack researchers discovered and authenticated a WordPress SQL Injection vulnerability and a stored XSS (Cross-Site Scripting) via Cross-Site Request Forgery (CSRF) issue with WP Fastest Cache plugin. Generally, exploits like these are reported to the plugin creator, who fix them, and issue an updated version of their plugin so that if you want to continue to safely use the plugin you simply need to update it.

In another WordPress SQL injection example, WPScan and Jetpack researchers uncovered a SQL Injection vulnerability in the All In One SEO plugin. If exploited, the SQL Injection vulnerability could grant attackers the ability to execute SQL commands and access to privileged information from the affected site’s database (e.g., usernames and hashed passwords). Again, the vulnerability was addressed by the plugin creator. 

Protecting your WordPress website against SQL injections

There is always a possibility of a WordPress SQL Injection attack, leading your site or sites to get hacked. This can be because of the vulnerability in the WordPress core, theme, or plugins. That’s why it is always recommended to update all of your software.

Fortunately, there are several steps you can take to protect your WordPress website from a SQL injection attack and other attacks:

Stay current. Perhaps the most important step is to always keep your WordPress installation up-to-date with the latest security patches released by its developers. Nearly half of WordPress installations aren’t using the most updated version. Therefore, you may want to consider enabling automatic updates to ensure that you’re always running the most recent version of WordPress. 

Password hygiene. Make sure that all users who have access to your administration panel use strong passwords so that attackers won’t be able to guess their way in. 

WordPress SQL Injection Protection tools. You should also install WordPress plugins for security like Jetpack or WPScan for additional protection against potential threats. Jetpack’s WordPress security plugin can monitor your site for vulnerabilities that could lead to SQL injections. This gives you the opportunity to fix them before someone takes advantage.

Edipsos, Greece

WAF. Another strategy you can use to protect against SQL injection in WordPress is to install a firewall or a WAF (web application firewall). Firewalls are network security system that helps you monitor and control the data coming into your WordPress site. This can catch and filter out malicious code, such as SQL injection attacks.

Additional Key features in a website firewall are protections against zero-day exploits protections from DDoS and brute force attacks.

Backup your WordPress Site. In addition to data theft, a hacker can also deface your site or erase it. These are additional reasons for making sure you take regular backups of your site.

Laguna de Apoyo, Nicaragua

Sanitize. You should also make sure that any user input is sanitized and validated before being used in an SQL query. By running the data through a validation process, you can make sure that any malicious code is removed and that only valid data is used in your queries. Additionally, you should avoid using user input as an element of an SQL WHERE clause or a LIMIT statement to prevent potential attackers from manipulating SQL queries.

Limit user privileges. Only those who need access have it; this will help reduce the likelihood of an attack occurring in the first place.  


The Jetpack blog has some good recommendations for what to do should your WordPress site fall victim to a malicious SQL injection attack. SQL injection attacks are a major threat for any WordPress website owner, but they don’t have to be something you fear if you take preventive measures such as keeping your software up-to-date and using strong passwords for all users with access rights. Additionally, installing security plugins like Jetpack or monitoring WordPress vulnerabilities with WPScan can help safeguard your website against potential threats, while limiting user privileges ensures that only those who need access will have it. By taking these precautions and following best practices when it comes to online security, you can rest assured knowing that your WordPress site is protected against malicious attackers seeking to gain unauthorized access through SQL injections.

Common Questions about WordPress SQL Injection Vulnerability

Mecca, Saudi Arabia

What is the difference between SQL injection and cross-site scripting (XSS)? SQL injection attacks are caused by a server-side vulnerability that targets the application’s database. Whereas, cross-site scripting is a client-side vulnerability causing a website to return malicious JavaScript that targets other application users.

What is the difference between SQL Injection attacks and Cross-Site Request Forgery (CSRF)? CSRF involves inducing a victim user to perform actions they do not intend to do.

How common are WordPress SQL Injection attacks? It is difficult to get reliable data about real-world SQL injection attacks, but vulnerabilities are common. SQL injection in WordPress is ranked as the second most critical vulnerability. Cybercriminals have likely tried using SQL injection to try and break into your website already. An older study by the Ponemon Institute on The SQL Injection Threat & Recent Retail Breaches found that 65% of the businesses surveyed were victims of a SQL injection-based attack.

WordPress itself is secure, however, third-party plugins and themes are not. At WPScan we have cataloged tens of thousands of vulnerabilities with our goal to prevent WordPress SQL injection.

Why do hackers target WordPress? WordPress websites are a common target for injection attacks, simply because WordPress is by far the most popular content management system and website builder. WordPress powers over 43% of all websites, meaning hundreds of millions of websites across the globe. Moreover, WordPress has the largest ecosystem of plugins and themes, granting more entry points for SQL injection.

What are well-known examples of SQL injection attacks? Target, Yahoo, Equifax, Epic Games, and Sony Pictures are examples of SQL injection attacks.

Is SQL injection considered a sophisticated attack? Researchers consider SQL injections as one of the least sophisticated, easy-to-defend-against cyber threats. Malwarebytes Labs ranked SQL injections as number three in their The Top 5 Dumbest Cyber Threats that Work Anyway, citing “the fact that SQLI is a known, predictable attack with easily implemented countermeasures.”

Leave a Reply