SQL Injection: What is It, How to Identify It, and How to Prevent It

Imagine waking up to find your website displaying odd messages or, even worse, sensitive customer data leaked. Alarming, right? SQL injection, a sneaky form of attack, can lead to these very scenarios, leaving many site owners puzzled and frustrated. Have you ever wondered how hackers manage to infiltrate databases so effortlessly or if your site might be at risk?

The problem is real and can affect any website that isn’t properly secured. Perhaps you’ve noticed unusual activity on your site or heard horror stories of data breaches affecting businesses. You might be asking yourself, “How can I tell if my website is vulnerable?” or “What can I do to prevent these attacks?”

If you suspect your site has experienced an SQL injection attack, scan your site for malware immediately.

TL;DR: SQL injection attacks exploit vulnerabilities in your website’s code to gain unauthorized access and cause significant damage. Protect your site with best practices and consider using MalCare’s comprehensive security solutions, including its Atomic Security firewall, for real-time protection against SQL injections.

The good news is that with the right strategies, you can protect your site. Let’s explore how to identify and prevent SQL injection to keep your website safe and sound.

What is SQL injection?

SQL injection is a type of cyber attack where malicious actors exploit vulnerabilities in a website’s database by injecting harmful SQL code. In simple terms, it’s like a hacker tricking your website into running harmful commands by inserting them into places where the site expects user input.

Here’s how it works: Imagine a login form where users enter their username and password. If the website doesn’t properly check these inputs, an attacker could enter malicious code that tricks the database into granting access without a valid username or password. For example, entering ‘ OR ‘1’=’1 into the username field could turn the SQL query into something always true, letting the attacker bypass the login.

SQL injection can target any part of a website that takes user inputs and processes them into SQL queries. Common entry points include login forms, search bars, URL parameters, and any form field interacting with the database, like contact forms. This makes it a widespread and dangerous vulnerability.

Why is this so dangerous? SQL injection can lead to data theft, data manipulation, gaining administrative access, website defacement, and even denial of service. In one notable case, 7-Eleven, a major convenience store chain, suffered an attack that resulted in millions of customer records being stolen, including credit card information, causing significant financial and reputational damage. Understanding the basics of SQL injection is crucial for protecting your website from such devastating attacks.

How to identify if your site has SQL injection vulnerabilities?

The primary reason SQL injection attacks succeed is due to vulnerabilities. These vulnerabilities are lapses in code, whether in the core, plugins, or themes. While we’ll dive into the details of how SQL injection exploits work later in the article, it’s important to understand that vulnerabilities serve as the entry points for these attacks.

There are several ways to determine if your site has a SQL injection vulnerability:

Check for updates

Ensure everything on your site is up to date. When a vulnerability is discovered in any software, developers typically release an update with a security patch. This is why keeping your site updated is crucial. Tools like MalCare can quickly scan for vulnerabilities and help you update your plugins and themes.

Use penetration testing tools

Tools like sqlmap and Invicti (formerly Netsparker) are popular for testing SQL injection vulnerabilities. They can help you identify weak points in your site.

Test with SQL code

If you have technical expertise, you can manually test your website by using specific SQL commands. Depending on your database, you can use a cheat sheet to find the right commands to try.

Online scanners

There are online scanners available that can test for SQL injection vulnerabilities. Tools like Acunetix, Website Vulnerability Scanner, and other open-source tools can be useful. However, these are primarily for testing and cannot protect your site from SQL attacks. To safeguard your website, you should install a website firewall like MalCare’s Atomic Security.

What to do if your site has SQL injection vulnerabilities?

The SQL injection exploit isn’t malware itself but a method to potentially insert malware into your site’s database or the site itself. If you discover a vulnerability on your website, the next step is to confirm whether malware is present. The best way to do this is by scanning your website for malware. Here are three ways to scan your site, ranked by effectiveness:

1. Deep scan with a security scanner: This method is the most thorough and can detect even the smallest traces of malware in your website or database. It’s the most reliable way to determine if your site has been compromised.
2. Online scanner: While less effective than a deep scan, using an online scanner can be a good first step to identify potential issues. It provides a quick overview of your website’s health.
3. Manual scanning: This is the least effective method and is not recommended. Manual scanning can easily miss hidden malware and is time-consuming.

In addition to scanning, be aware that malware may not always be obvious. Look out for these symptoms:

One of these symptoms could be an anomaly, but multiple signs are a strong indicator of malware.

Once you’ve confirmed your site has malware, prioritize removing it immediately. Malware can cause increasingly severe damage over time. Here are three methods to clean your site:

1. Use a security plugin: This is the option we recommend. Tools like MalCare can clean malware from your site in minutes, targeting only the malicious code and keeping your data intact. Simply install the plugin, activate it, and follow the instructions to scan and clean your site.
2. Hire a maintenance service: You can also hire a security expert or maintenance service to clean your site. Be aware that these services can be expensive and may not always guarantee a complete cleanup.
3. Manual cleaning: We do not recommend manual cleaning due to the risk of human error and the time it takes. However, if you choose this route, follow our detailed hacked site guide to avoid missing any malware.

After removing the malware, take these additional steps to secure your site:

Assume that sensitive information like passwords may have been compromised and take action to secure your site comprehensively.

How to prevent SQL injection attacks on your site?

The best way to handle malware and exploits is to prevent them from happening. To protect your website from SQL injection attacks, follow these steps to ensure maximum security:

Use a firewall: Firewalls are your best defense against SQL injection attacks. As a website admin, you might not be able to fix underlying code issues, but you can install a robust firewall. Choose a firewall like MalCare’s Atomic Security, which integrates deeply with your site and blocks attacks such as SQL injections, remote code execution, and cross-site scripting using specialized rules.

Update all your plugins and themes: Keeping everything on your website updated is crucial. Updates often contain security patches for vulnerabilities. Delaying updates can leave your site exposed to SQL attacks and malware.

Avoid nulled software: Always choose legitimate extensions. Nulled plugins and themes are ticking time bombs. They often come with pre-installed malware or backdoors that can be exploited. Plus, you can’t update them, which means vulnerabilities in the original version will remain in the nulled ones permanently.

Install a security plugin: A security plugin is essential for staying on top of website security. You need a scanner that runs daily. MalCare’s scanner, for example, scans daily for malware and vulnerabilities, and you can clean your site in minutes if needed.

Website hardening: Beyond good security practices, you can harden your website. We recommend disabling XML-RPC and enabling two-factor authentication for added protection.

If you’re a developer or creating custom code for your website, here are additional steps to prevent SQL injection vulnerabilities:

Use prepared statements: Send user inputs from forms to a function for checks, store them in a variable, and then pass them to the statements. This way, inputs aren’t directly embedded into commands and executed.

Use stored procedures: Stored procedures should be used to create SQL statements with parameters, which are stored in the database and called by the application. This prevents any external interference when executing SQL queries.

Sanitize user inputs: Validate user inputs by stripping out special characters that are SQL operators and disallow them in passwords. Your system should reject these symbols outright.

Separate data from commands: Keep your data separate from commands. OWASP has a great guide on how to do this.

Control error reporting: Configure error reporting on your site such that it does not display error messages on the client web browser. This prevents hackers from getting insights into your site’s working and exploiting it to gain unauthorized access.

Use frameworks: Many frameworks have built-in functions that use prepared statements, so you don’t have to write SQL statements directly in your code.

Limit database access: Restrict database access to only those who need it.

There are plenty of coding resources available to help you from a development perspective. By following these steps, you can significantly reduce the risk of SQL injection attacks on your website.

What is the impact of SQL injection attacks?

SQL Injection attacks can cause significant damage to your website and business. When an attacker exploits a vulnerability, the consequences can be severe and far-reaching.

First, there’s the risk of data theft. Attackers can access sensitive information, such as customer details, credit card numbers, and personal data. This not only violates privacy but can also lead to legal issues and loss of customer trust.

Next, data manipulation is another concern. Attackers can alter, delete, or insert data in your database. Imagine someone changing product prices, deleting user accounts, or adding fake entries. This can disrupt your business operations and lead to financial losses.

Gaining administrative access is a worst-case scenario. If attackers gain admin rights, they can take full control of your website. They can lock you out, change settings, or even deface your site. This can severely damage your reputation.

Website defacement is another impact. Attackers can change the content on your site to display unwanted messages or images. This can be embarrassing and harm your brand’s image.

Lastly, there’s the risk of a denial of service (DoS) attack. Attackers can execute resource-intensive queries, making your website slow or completely unavailable to users. This can lead to lost revenue and frustrated customers.

How are SQL injection attacks executed?

SQL Injection attacks exploit vulnerabilities in your website’s code. Attackers use these weaknesses to inject malicious SQL code into your database queries. Here’s a simple breakdown of how these attacks are executed.

Imagine a login form where users enter their username and password. The website might process this input using an SQL query like this:

SELECT * FROM users WHERE username = 'user_input' AND password = 'user_input';

If the application doesn’t properly sanitize the inputs, an attacker could enter something like this into the username field:

' OR '1'='1

The resulting SQL query would then look like this:

SELECT * FROM users WHERE username = '' OR '1'='1' AND password = 'user_input';

This query is always true because ‘1’=’1′ is always true, allowing the attacker to bypass authentication and gain unauthorized access.

Attackers can also use advanced techniques to extract data, update records, or even delete tables. They often use automated tools to find and exploit these vulnerabilities quickly.

Tools used by attackers include sqlmap, a popular tool for automating SQL Injection attacks. It can scan websites, identify vulnerabilities, and exploit them with minimal effort.

SQL Injection can target any part of a website that processes user inputs into SQL queries. Common entry points include:

What are the types of SQL injection attacks?

SQL injection attacks come in three flavors: in-band SQL injection, inferential SQL injection, and out-of-band SQL injection.

1. In-band SQL injection

In-band SQL injection is the most common type. Here, attackers use the same channel to both launch their attack and gather results. It’s like a one-stop shop for hackers. Two popular techniques fall under this category:

Error-based SQL injection: Attackers use SQL commands to force the database server to generate error messages. These error messages can reveal details about the database structure. While handy during development, these messages become vulnerabilities once your site is live. To prevent this, disable error messages on your live site.

Union-based SQL injection: This technique uses the UNION SQL operator to combine multiple select statements into a single HTTP response. It allows attackers to extract information from the database. This method is more common and requires robust security measures to combat.

2. Inferential SQL injection

Also known as blind SQL injection, inferential SQL injection doesn’t directly transfer data to the attacker. Instead, attackers send data payloads and observe the responses to infer information about the database structure. This type is less common because it takes longer to execute. There are two main techniques:

Boolean injection: Attackers send SQL queries and observe the results. They infer whether a query is true or false based on changes in the HTTP response.

Time-based injection: Attackers send SQL queries that make the database wait a certain number of seconds before responding. By measuring the delay, they can determine if the query is true or false. For example, a query might ask for a delay if the first letter of the database name is ‘A’. If the response is delayed, the attacker knows the query is true.

3. Out-of-band SQL injection

Out-of-band SQL injection is the least common. Here, attackers use one channel to send the attack and a different channel to gather results. This method is useful if the server is too slow or unstable for other types of SQL injection attacks.

Why are SQL injection attacks so common?

SQL injection attacks are one of the oldest and most prevalent forms of cyber attacks, and there are several reasons why they remain so common.

Easy to execute

One of the main reasons SQL injection attacks are so widespread is that they are relatively easy to execute. An attacker doesn’t need to be a highly skilled hacker to perform an SQL injection. With basic knowledge of SQL and a few readily available tools, even a novice can launch an attack. There are numerous tutorials and guides online that can walk someone through the process step-by-step.

Widespread SQL usage

SQL is a widely used language for managing and manipulating databases. Almost every web application that stores data uses SQL in some form. This ubiquity means there are countless potential targets for SQL injection attacks. From e-commerce sites to social media platforms, any site that interacts with a database can be vulnerable.

Poor coding practices

Many developers, especially those new to coding, might not be aware of the importance of securing their SQL queries. They might write code that directly includes user inputs in SQL statements without proper validation or sanitization. This oversight creates vulnerabilities that attackers can easily exploit. Even experienced developers can make mistakes or overlook security best practices, leading to potential weaknesses.

Legacy systems

Older systems and applications that were built before SQL injection became a well-known threat might not have adequate security measures in place. These legacy systems often continue to run without updates or patches, making them prime targets for attackers. Organizations sometimes delay updating these systems due to cost, complexity, or fear of breaking functionality, further increasing the risk.

Automated tools

Attackers have access to sophisticated automated tools that can scan websites for SQL injection vulnerabilities. Tools like sqlmap can identify and exploit these weaknesses with minimal effort. This automation means that even small websites with limited traffic can be targeted by attackers looking for easy wins.

High reward

The potential rewards for a successful SQL injection attack are significant. Attackers can gain access to sensitive data, such as personal information, credit card details, and login credentials. This data can be sold on the dark web or used for further malicious activities. The high potential payoff makes SQL injection attacks an attractive option for cybercriminals.

Inadequate security measures

Many organizations, especially smaller ones, may not have the resources or expertise to implement robust security measures. They might lack the necessary tools, knowledge, or personnel to detect and prevent SQL injection attacks. This gap in security can leave them vulnerable.

Final thoughts

SQL injection attacks remain a significant threat to websites of all sizes, but understanding how they work and taking proactive steps can greatly reduce your risk. By following best practices like using prepared statements, validating user inputs, and keeping your software updated, you can create a robust defense against these attacks. It’s essential to stay vigilant and regularly review your security measures to ensure they are up to date.

For an added layer of protection, consider using MalCare and its Atomic Security firewall. MalCare not only offers comprehensive malware scanning and removal but also provides specialized rules to block SQL injection attacks. Its Atomic Security firewall deeply integrates with your site, offering real-time protection against various threats, including SQL injections, remote code execution, and cross-site scripting.

FAQs

What is SQL injection?

SQL Injection is a cyber-attack where malicious SQL code is inserted into a query, allowing attackers to access, manipulate, or delete data in your database.

Why are SQL injection attacks so common?

SQL Injection attacks are common because they are easy to execute, SQL is widely used, and many websites have poor coding practices. Additionally, automated tools make it simple for attackers to find and exploit vulnerabilities.

What are some signs that my website has been compromised by an SQL injection attack?

Signs include unusual error messages, unexpected changes in your database, unauthorized administrative access, website defacement, and performance issues. Look for spam in Google search results, security warnings, and sudden spikes in traffic.

How can I prevent SQL injection attacks?

Preventing SQL Injection involves using prepared statements, validating and sanitizing user inputs, keeping your software updated, avoiding nulled plugins and themes, and employing a robust firewall.