Do you know about the growing danger of SQL injection vulnerabilities? In the last quarter of 2022, AppTrana prevented 1,111,548 of these attacks. With over a million SQL injection attacks blocked in just three months, it’s clear that web applications are under attack. 

To stay safe and protect your business, here's a guide to understanding this OWASP top 10 vulnerability and preventing SQL injection attacks.

What are Database and SQL?

A database is like a collection of organized tables where data can be stored and accessed. To interact with a database, a database application needs a way to communicate between the user interface (front end) and the database itself. This is where SQL (Structured Query Language) is used.

What does SQL Injection stand for?

Structured Query Language (SQL) was developed in the 1970s and is used to access and manage data in a database. Applications use SQL statements to communicate with the database, allowing them to perform operations like selecting, updating, inserting, deleting, creating, and dropping data.

SQL injection (SQLi) attacks occur when attackers use input fields in web applications to run unauthorized queries on the server. This can give them access to information they shouldn't have. SQL injection attacks are considered high impact and are categorized as such by OWASP Top 10.

What causes SQLi?

SQL injection (SQLi) attacks typically occur due to a lack of proper sanitization of user input. When an application doesn't validate user input in SQL statements, attackers can insert additional commands into SQL queries. This can lead to unauthorized access, data modification, or other harmful actions.

For instance, attackers might use SQL injection to bypass authentication by creating a query that always returns true, granting them access without a valid username and password. They could also manipulate data, steal sensitive information, or execute malicious actions through SQL injection.

How does SQL Injection Work?

Here’s an example to illustrate how SQL Injection works:

Imagine there's a website that uses a SQL database to store user details. On this website, there's a login form where users input their usernames and passwords. The website's code could be similar to the following:

$username = $_POST[‘username’];
$password = $_POST[‘password’];
$sql = “SELECT * FROM users WHERE username=’$username’ AND password=’$password'”;
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result) > 0) {
// User has successfully logged in
} else {
// Invalid username or password
}

In this code, user input is directly inserted into the SQL statement. If a user enters a username like `admin'--`, the SQL statement becomes:

```sql

SELECT * FROM users WHERE username='admin'--' AND password=''

```

The double dash `--` is a comment character in SQL, so everything after it is ignored. This allows the attacker to bypass the password check and log in as the administrator.

Attackers use various SQL injection commands to see which ones the database executes. They then continue to execute SQL injection attacks to access the necessary information. They may stop after obtaining what they need or continue exploiting the vulnerabilities until they are fixed.

What are the Types of SQL Injection Attacks?

Different types of SQL injection attacks have distinct characteristics. Here are some common types:

1. Error-Based SQL Injection: Exploits errors generated by the database to extract information.

2. Union-Based SQL Injection: Uses the UNION SQL operator to combine the results of two or more SELECT statements, allowing attackers to retrieve data from other tables.

3. Blind SQL Injection: Does not rely on error messages but rather sends requests to the database and interprets the response to infer information.

4. Time-Based Blind SQL Injection: Delays in the server's response to determine if the injected query is true or false.

5. Boolean-Based Blind SQL Injection: Relies on the application's response to different conditions to infer information about the database.

How are SQL Injections Bot-Driven?

SQL injection attacks can be automated by bots in several ways. Bots can scan websites for vulnerabilities and attempt to exploit them using SQL injection techniques. Here are some examples:

1. Automated scanning: Bots can automatically scan websites to find vulnerabilities that SQL injection attacks can exploit. Once a vulnerable site is found, the bot can attempt to exploit it using a set of pre-defined SQL injection payloads.

2. Brute-force attacks: Bots can conduct brute-force attacks on web forms, like login pages or search boxes, to inject SQL code into the application. They use techniques like dictionary attacks or fuzzing attacks to generate different payloads and submit them to the application to find a vulnerable entry point.

3. Automated exploitation: Once a vulnerable entry point is discovered, bots can automate the process of injecting malicious SQL code and extracting data from the database. They can use techniques like blind SQL injection or error-based SQL injection to extract sensitive information.

Overall, bots can automate the process of identifying and exploiting SQL injection vulnerabilities on a large scale, making it easier for attackers to compromise websites and extract sensitive data. It's crucial to implement robust security measures to prevent SQL injection attacks.

What are the Impacts of Injection Attacks?

SQL injection attacks can have significant and varied impacts depending on the target. The most common consequences include data integrity and confidentiality breaches:

1. Stealing sensitive data: Attackers can extract confidential information such as usernames, passwords, credit card numbers, and personal details from a database.

2. Modifying or deleting data: SQL injection can lead to unauthorized manipulation or deletion of data, causing potential data loss or damage.

3. Taking control of a system: Attackers can gain administrative access, enabling them to control a system and perform further malicious activities like additional attacks or malware installation.

The potential costs of an SQL injection attack are substantial. There can be direct losses, such as the cost of restoring systems and data, as well as indirect losses like lost revenue due to business operations disruption. Businesses may also face financial penalties or legal action due to data breaches caused by injection attacks, particularly those handling sensitive information like financial or healthcare institutions.

Reputation damage can be long-term and challenging to recover from, impacting the company's future growth and profitability. Additionally, downtime resulting from attacks can lead to lost revenue and customer frustration, further harming the business's reputation. Hackers have increasingly combined SQL injection attacks with other techniques like insufficient authentication, DNS hijacking, XSS, and DDoS attacks to cause more extensive financial damage and complete host takeovers.

How to Prevent SQL Injection Attacks?

To stop SQL injection attacks, make sure all fields are protected from incorrect inputs and unauthorized application execution.

While checking inputs on the client side can prevent incorrect inputs and improve user experience, it's not enough to stop malicious users.

Therefore, it's crucial to validate inputs on the server side, ideally where SQL queries are created, to prevent SQL injection attacks.

While input validation is the primary defense against injection attacks, it's important to have multiple layers of defense. Implementing measures like limiting database user privileges and using parameterized queries can significantly reduce the risk of SQL injection in your application.

7 Effective SQL Injection Prevention Techniques

Here are 7 effective techniques to prevent SQL injection attacks:

1. Implement Input Validation and Sanitization: Ensure user inputs meet expected formats and remove potentially harmful elements.

2. Apply Escaping Techniques: Modify user inputs to neutralize special characters that could be used for malicious SQL injection.

3. Utilize Parameterized Statements: Use placeholders in SQL queries to separate user inputs from the query, eliminating the need for manual escaping.

4. Incorporate Stored Procedures: Define parameterized procedures in the database to minimize injection risk by executing procedures without directly incorporating user inputs.

5. Conduct Continuous Scanning and Penetration Testing: Regularly audit and review the application's codebase to identify and address potential vulnerabilities.

6. Adopt the Least Privilege Principle: Limit permissions to the minimum necessary to reduce the impact of a successful attack.

7. Deploy Web Application Firewalls (WAF): Monitor and filter incoming HTTP traffic to detect and block SQL injection attempts, adding an extra layer of defense.

Prevent SQL Injection with AppTrana

Protect your website from SQL injection attacks with AppTrana's Web Application Firewall (WAF). AppTrana analyzes incoming traffic to your web application, detecting and blocking malicious SQL code before it reaches your application, preventing attacks.

AppTrana uses machine learning, rule-based, and behavioral-based detection techniques to identify and block SQL injection attacks effectively.

Moreover, AppTrana offers real-time visibility and reporting on incoming traffic, allowing you to monitor your application's security and respond swiftly to potential threats.

Start by assessing your website's SQL injection risks with AppTrana's Free Trial.