Mar 17, 2025 Information hub

What is SQL injection (SQLi)?

In the fast-paced world of cybersecurity, few threats have proven as enduring—or as destructive—as the question: What is SQL Injection (SQLi)? This vulnerability lets attackers manipulate database queries, exposing sensitive information, altering data, or even taking down entire systems. From headline-making breaches to silent intrusions, understanding SQLi remains a top concern for businesses and developers. As of March 17, 2025, with web applications powering everything from e-commerce to government services, mastering SQL Injection (SQLi) and its prevention is more urgent than ever.

Why should you care about SQLi. A single attack can spill passwords, credit card numbers, or personal details, costing millions and eroding trust. Despite its age, this exploit thrives due to coding oversights and lax security practices. In this in-depth guide, we’ll unpack What is SQL Injection (SQLi)?, how it works, its real-world impact, and actionable steps to stop it. Whether you’re a developer, security pro, or business owner, this post has you covered.

Table of Contents

Unpacking What is SQL Injection (SQLi)?

Defining the Basics

So, What is SQL Injection (SQLi)? It’s a web security flaw where attackers inject malicious SQL code into an application’s database queries. It happens when user inputs—like form fields or URL parameters—aren’t properly checked before being added to a SQL statement. This lets attackers bypass security, access unauthorized data, or tamper with the database.

Take a login form, for example. A typical query might look like:

SELECT * FROM users WHERE username = 'user' AND password = 'pass';

If the input isn’t sanitized, an attacker could enter ' OR '1'='1 as the username, turning the query into:

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

Since '1'='1' is always true, the password check is ignored, and the attacker gains access. That’s a clear answer to SQLi.

Why It Still Matters in 2025

You might wonder why SQL Injection (SQLi) still haunts the web after over 20 years. OWASP lists injection attacks, including this one, in its Top 10 vulnerabilities year after year. In 2023, Verizon’s Data Breach Investigations Report pegged SQLi as a factor in 8% of web app attacks. SQL databases—like MySQL and PostgreSQL—power most applications, and developers still make preventable mistakes.

How Does SQL Injection (SQLi) Work?

Types of Vulnerabilities

To grasp What is SQL Injection (SQLi)?, know it comes in several forms:

Classic: Direct input manipulation, like tweaking a login field.
Blind: Subtle, with no visible output—attackers guess data via response changes.
Union-Based: Uses UNION to pull data from other tables.
Second-Order: Stores malicious input for later execution.

Exploiting What is SQL Injection (SQLi)?

Let’s explore What is SQL Injection (SQLi)? with practical cases.

Example 1: Retrieving Hidden Data

An online store URL might be:

https://example.com/products?category=Electronics

It triggers:

SELECT * FROM products WHERE category = 'Electronics' AND available = 1;

An attacker tweaks it to:

https://example.com/products?category=Electronics' OR 1=1--

The query becomes:

SELECT * FROM products WHERE category = 'Electronics' OR 1=1--' AND available = 1;

The -- comments out the availability check, showing all products.

Example 2: Bypassing Authentication

For a login, an attacker enters:

Username: admin'--
Password: (blank)

The query:

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

This logs them in as “admin” without a password.

Example 3: Union Attack

Using:

https://example.com/products?category=' UNION SELECT username, password FROM users--

The query:

SELECT * FROM products WHERE category = '' UNION SELECT username, password FROM users--';

This leaks user credentials alongside product data.

Detecting SQL Injection (SQLi)?

Testers spot SQLi by:

Injecting single quotes (') to trigger errors.
Using Boolean tests (OR 1=1) to spot response shifts.
Adding delays (SLEEP(5)) for blind cases.
Running tools like Burp Suite.

The Impact of SQL Injection (SQLi)?

Real-World Fallout

What is SQL Injection (SQLi)? It’s fueled major breaches:

Sony Pictures (2011): 77 million PlayStation accounts exposed, costing $170 million.
Heartland (2008): 130 million credit cards stolen via this method, with $140 million in losses.
Equifax (2017): Poor input handling aided a breach impacting 147 million people.

Stats and Trends

IBM’s 2024 breach report: Injection-related breaches cost $4.45 million on average.
Imperva 2023: 19% of web apps are still vulnerable to SQLi
Automated tools make attacks easier for novices.

Long-Term Damage

Beyond data theft, What is SQL Injection (SQLi)? can create backdoors, risking GDPR fines up to €20 million or 4% of revenue.

Trends and Challenges SQL Injection (SQLi)?

Evolving Tactics

Attackers keep innovating around SQL Injection (SQLi)?:

Obfuscation: Encoding payloads to dodge WAFs.
Automation: Bots scan millions of sites for flaws.
API Targets: JSON and XML inputs open new attack paths.

Defender Struggles

Legacy Code: Old systems lack modern safeguards.
Awareness Gaps: Developers still misuse string concatenation.
Complex Queries: Dynamic SQL complicates fixes.

What’s Next?

This vulnerability will evolve with tech:

AI may boost detection.
Serverless apps could shift risks.
Regulations may tighten coding rules.

Preventing SQL Injection?

Parameterized Queries: Your Best Defense

A key answer to SQLi is prevention via parameterized queries. They separate data from code, blocking input from altering query logic.

Vulnerable:

String query = "SELECT * FROM users WHERE username = '" + input + "'";
Statement stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery(query);

Secure:

PreparedStatement stmt = connection.prepareStatement("SELECT * FROM users WHERE username = ?");
stmt.setString(1, input);
ResultSet rs = stmt.executeQuery();

More Safeguards

Input Validation: Allow only expected characters.
ORM Tools: Use frameworks like Hibernate.
Escaping: A last-ditch fix if concatenation is unavoidable.
Least Privilege: Limit database permissions.
WAFs: Filter bad requests.

Why It Pays Off

Cuts breach risks.
Saves money on fines.
Boosts trust.

Tools and Resources

Testing SQLi

Manual: Try ' OR 1=1-- or SLEEP(10).
Tools: Burp Suite, SQLMap, OWASP ZAP.
Labs: Practice on PortSwigger Labs

Handy Guides

SQL Injection Cheat Sheet
OWASP secure coding tips.

Conclusion

What is SQL Injection (SQLi)? It’s a stubborn threat in 2025, thriving on its simplicity and the havoc it wreaks. From data theft to logic subversion, it exploits trust in user input, with breaches like Sony’s proving its cost. Trends like automation and API attacks show it’s not going away—but it’s beatable.

Take Action

Audit your code with Burp Scanner.
Use prepared statements now.
Train your team on this vulnerability.
Keep up with new threats.