SQL Injections And WordPress

WordPress is becoming more widely used in data-driven applications. As a result, a vulnerability known as SQL injection has become a major threat.

In this article, we will take a look at some real-world examples of SQL injection attacks and examine what you can do to protect your website from them.

What is an SQL Injection Attack?

An SQL injection attack is one in which the attacker sends SQL commands to the back-end database, typically with the intention of retrieving data. If an attacker successfully exploits the SQL injection vulnerability, they will gain unrestricted access to the database server and all of the contained information.

As a result, the database executes the code of the attacker and enables them to make changes and cause damage to a website.

The SQL injection vulnerability

When the code does not properly sanitize the user inputs and the database application receives and uses that input to generate database queries, this creates a vulnerability known as SQL injection.

The result of neglecting to strip or encode characters that could modify the query structure can lead to such attacks. The attacker can insert and execute malicious SQL statements, which might have potentially disastrous results.

Real-World Examples of SQL Injections

We will try to explain how this works by giving a simple example.

Let’s say you run an online shop. When a visitor chooses a product category, for example ‘Watches’, the corresponding URL would be something like this:

https://the-eshop.com/products/watches/

This is the canonical URL though. The real URL would be like this:

https://the-eshop.com/products?category=watches

Now the corresponding query to that URL would look like this:

SELECT * FROM products WHERE category = 'watches' AND released = 1

What this query does is select all the details (SELECT *) from the “products” database table (FROM products) and retrieve those that belong to the “watches” category (WHERE category = ‘watches’) and that are released (AND released = 1).

This also means that if you attempt to enter category=shoes after https://the-eshop.com/products? , you will be redirected to the category with the slug “shoes”, if it exists.

But the problem starts when the attackers enter a string that includes special characters.

If the data is sent to the query without being sanitized first, it means you have a vulnerability. The attacker can do things he is not normally allowed to do with your database by using the appropriate input.

If the attacker enters category=watches'-- then the query will become:

SELECT * FROM products WHERE category = 'watches'--' AND released = 1

In SQL, the double dash is used to comment what follows. So what the above actually does is get all the products of the category with the slug “watches ” no matter if they are released or not. In another scenario, in the same way, the attacker could drop a whole table or do worse damage.

The impact of SQL injection attacks

Attacks using SQL injection are extremely problematic since they have the potential to damage the integrity of the entire database or even the server itself.

With the same logic we explained above, it is possible for the attacker to get unauthorized access to sensitive data, such as passwords, credit card numbers, or other personal user information. They can retrieve hidden data or data from other database tables, change the logic of the query and more.

This can result in reputational damage as well as long-term compromise, both of which, depending on the sort of attack, may go undiscovered for a considerable amount of time.

How to Prevent SQL Injections

Let’s see what we can do to protect our website from SQL injections.

Keep your WordPress Core, Plugins and Themes up-to-date

One of the most effective ways to prevent SQL injection exploits is to always use the most recent version of WordPress. This is because newer versions of WordPress likely already included fixes to prevent the most common types of attacks.

The same goes for your plugins and themes. Reputable authors are a0 less likely to release products that contain security flaws in the first instance whilst b) are probably going to patch any issues should they arise asap.

Choose Plugins Wisely

Since input sanitization is so important, take your time to review the plugins you want to use in each case. You will have to make sure that their developers have professionally coded the plugin and taken security best practices into account.

We have more information on this and also other top tips for securing your WordPress website in this guide.

Use WordPress Prepared Statements

When working with WordPress, you can also benefit from using prepared statements which are a way to execute an SQL query safely.

A generic rule of thumb regarding WordPress and protection from SQL injections is to always use the WordPress built-in functions when interacting with the database.

Conclusion

SQL injections are among the most common types of WordPress attacks (along with XSS attacks). As such it’s vital you take the steps required to avoid suffering such an attack on your website. This is especially critical if you’re not using a host that helps mitigate these types of events for you.

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