What is SQL Injection and how to protect your website?

SQL Injection (SQLi) is one of the most common and dangerous attack techniques that cybercriminals use to exploit vulnerabilities in websites and databases. This technique allows attackers to inject malicious SQL code into input fields to gain unauthorized access, steal sensitive information, or manipulate data. Learn how to protect yourself against SQL Injection.

What exactly is SQL Injection?

In an SQL Injection attack, a hacker inserts malicious SQL code into an input field, enabling them to manipulate underlying database queries. This can lead to extracting confidential information, modifying or deleting data, or even gaining full control over the database. SQL stands for Structured Query Language.

A well-known example of an SQL Injection attack occurred at the American company Heartland Payment Systems in 2008, where millions of credit card records were stolen.

This incident highlighted how severe the consequences of an SQL Injection attack can be. Other well-known companies such as Sony and Yahoo! have also fallen victim to such attacks.

How does SQL Injection work?

An SQL Injection attack occurs when an application fails to properly validate user input and directly processes it in an SQL query. A lack of parameterization can also contribute to the vulnerability.

This allows attackers to manipulate SQL queries and gain access to data that should normally be restricted.

Example of an SQL Injection

If a website verifies a username and password using the following (vulnerable) SQL query:

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

An attacker can manipulate the password field with:

' OR '1'='1' --

Resulting in:

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

Since the condition '1'='1' is always true, the attacker gains access without entering a valid password.

Types of SQL Injection attacks

Error-based SQL Injection

This technique forces the database to display error messages that can reveal valuable information about the database structure. This is particularly relevant in databases like Microsoft SQL Server, which often provide detailed technical error messages useful to attackers.

Union-based SQL Injection

Here, the hacker uses the UNION operator to combine results from multiple tables, extracting additional data.

Blind SQL Injection

In a Blind SQL Injection, the attacker does not receive direct error messages but can infer database information through yes/no questions.

Time-based SQL Injection

The attacker manipulates the database to introduce delays, allowing them to determine if the attack was successful.

Consequences of a successful SQL Injection attack

A successful SQL Injection attack can have devastating consequences:

• Data breaches: Sensitive information like passwords, emails, and financial data can fall into the wrong hands.
• Data modification or deletion: Attackers can alter or delete records, leading to data loss and corruption.
• Complete system takeover: In some cases, hackers can gain full control over the server through SQLi.

Additional security risks of SQL Server and SQL Injection

In databases such as SQL Server, SQL Injection attacks are particularly dangerous because they often contain critical business information.

A criminal can execute commands beyond just retrieving data. By leveraging certain characters and syntax in SQL Server, a hacker could modify database configurations or create new users with elevated privileges.

Since SQL Injection works by placing uncontrolled input directly into an SQL query, developers must always validate input and use parameterized queries.

Without these measures, a simple SQL Injection attack can escalate into a full takeover of the database and potentially even the underlying server.

How to Prevent SQL Injection?

✅ Use of parameterized queries and prepared statements

Parameterized queries separate user input from SQL queries, significantly reducing the risk of injection.

Example in PHP with MySQLi:

$stmt = $conn->prepare("SELECT * FROM users WHERE username = ? AND password = ?");

$stmt->bind_param("ss", $username, $password);

$stmt->execute();

✅ Validation and sanitization of input

Check and filter all user input to allow only authorized values.

✅ Limit database priviliges

Grant applications only the minimal and necessary database privileges.

✅ Perform SQLInjection testing

Regularly testing for SQL Injection vulnerabilities helps detect issues early. Tools like SQLMap can assist in this process.

✅ Use a Web Application Firewall (WAF)

A WAF helps block malicious SQL queries before they reach the database.

✅ Encrypt sensitive data

Even if a hacker gains access to the database, encryption makes it harder to retrieve useful information.

✅ Conduct regular penetration testing

Ethical hackers can test your systems for vulnerabilities and help you fix detected issues promptly.

✅ Use monitoring tools

Software like Intrusion Detection Systems (IDS) can detect suspicious database activity and alert you to potential attacks.

How does Combell protect your website against SQL Injection?

Combell provides an extensive security solution called Combell Shield, protecting against SQL Injections, malware, and other cyber threats. Combell Shield is robust due to:

• Advanced Web Application Firewall (WAF): Detects and blocks malicious SQL queries before they cause harm.
• Continuous monitoring: Suspicious activities are detected in real-time and automatically reported.
• Automatic updates and patches: Security vulnerabilities are quickly fixed to minimize risks.
• DDoS protection: Prevents large-scale attacks from taking your website offline.

With Combell Shield, you not only get protection against SQL Injections but also ensure a secure and reliable online environment for your users!

Prevent SQL Injection with Combell Shield

Security is essential for every website. Combell Shield provides protection against SQL Injections, malware, and hackers. With continuous monitoring and advanced firewall protection, you are assured of a secure hosting environment.

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Frequently asked questions about SQL Injection