Web Security (OWASP Top 10): How SQL Injections Break Businesses and What Real Practice Teaches

Imagine an online store that accepts orders around the clock. Suddenly, a strange request appears in the logs: someone entered ' OR 1=1 -- in the search field. Within minutes, the database starts returning all products, including hidden ones, and then the users table with password hashes. This is not a movie scenario but a classic SQL injection (SQLi) — one of the oldest and still alive attacks in web security.

Understanding the OWASP Top 10 is not about memorizing a list of vulnerabilities. It's about being able to see how an innocuous-looking input field turns into an entry point for an attacker. And about building defenses so that one mistake doesn't cost a company its reputation and money.

In this article, we'll break down why web security is more complex than it seems, where even experienced developers most often fail, and how to build a learning path that goes beyond reading documentation.

Why SQL injections are still at the top even though everyone knows about them

SQL injection occurs when an application concatenates user input with an SQL query. If the string SELECT * FROM users WHERE name = ' + user_input + ' reaches the database without processing, an attacker can substitute anything. The problem is not that developers haven't heard of SQLi, but that protection is often implemented inconsistently.

Here's a typical example of vulnerable Python code (pseudocode):

query = "SELECT * FROM users WHERE login = '" + login + "' AND password = '" + password + "'"
cursor.execute(query)

If login is admin' --, the query becomes SELECT * FROM users WHERE login = 'admin' --' AND password = '...'. Everything after -- is considered a comment, and password verification is disabled. The result is login without a password.

The correct solution is parameterized queries (prepared statements). In the same Python with psycopg2, it looks like this:

cursor.execute("SELECT * FROM users WHERE login = %s AND password = %s", (login, password))

The driver escapes the values itself. But even here there are pitfalls: if you use an ORM and manually build conditions via concatenation, protection is bypassed. For example, in SQLAlchemy the expression text("SELECT * FROM users WHERE id = " + user_id) is again vulnerable, although the ORM is secure "out of the box."

Where mistakes most often occur

• Dynamic table or column names. Parameterization does not work for identifiers (table names, columns). If the application allows choosing sorting via the ?sort=price parameter, an attacker can substitute price; DROP TABLE users--. Protection is a whitelist of allowed values.
• Stored procedures with dynamic SQL. Inside a procedure, you can again build a string and execute it via EXECUTE, which reintroduces the vulnerability.
• Incorrect privilege settings. Even if an injection exists, but the database user only has read rights to one table, the damage is less. The principle of least privilege is still relevant.

Real case analysis: how SQLi in a feedback form led to a database leak

Imagine a company that develops CRM for small businesses. The feedback form has a "Subject" field. The developer used concatenation to build an insert query into the tickets table. The attacker submitted the subject: '); SELECT * FROM users; --. As a result of the query execution, all users were selected, and the data went into the server response, which the attacker read through an error.

What went wrong:
1. The application displayed database error details on the page (verbose error). This gave the attacker feedback.
2. The database user's privileges allowed reading the users table from the same connection.
3. There was no input validation or parameterization.

How it was fixed:
- All queries were rewritten to prepared statements.
- A separate database user was introduced for the web application with rights only to tickets (INSERT) and users (SELECT by id).
- Logging of suspicious queries was set up, and error output was disabled in production.

Result: the vulnerability was closed, but the company spent two weeks on audit and fixes, and also notified clients about the incident. Losses were reputational and time-related.

This case shows that protection is not a single mechanism but a combination of practices: secure queries, minimal privileges, error handling.

Where the protection scheme itself breaks (failure modes)

Even if you use parameterization and an ORM, there are scenarios where protection stops working. Let's consider three typical failures.

1. Conditions changed: migration to a new DB or driver

You updated the database driver, and the parameterization syntax changed. For example, in some drivers placeholders ? are replaced with $1, but old code still uses ?. Queries start failing, and developers hastily revert to concatenation to "quickly fix." How to notice in advance: cover critical queries with tests that check not only the result but also the absence of injections (e.g., using sqlmap in a test environment). What to do if it's too late: audit all queries after migration, use static code analysis.

2. The rule is not applied: third-party library or API

You connected a library for report generation that internally builds SQL queries from user filters. It may be vulnerable even if your code is clean. How to notice: check dependencies with SCA tools (e.g., OWASP Dependency-Check), read changelogs for security fixes. What to do: replace the library or wrap its calls in additional validation.

3. Deadline expired: outdated validation rules

You used regex to filter dangerous characters, but a new DB version supports other functions that can be used for injections. Blacklists always lag. How to notice: regularly review rules and switch to whitelists. What to do: replace filtering with strict typing and parameterization.

Paths to mastering web security: an honest trade-off

You can learn the OWASP Top 10 in different ways. Here are three main paths and their cost.

Self-study often hits the lack of feedback: you don't know if you understood the material correctly until you face a real attack. Practice on ranges gives attacking skills, but protection requires a different mindset — designing secure architecture.

The course Web Security (OWASP Top 10) bridges exactly this gap: it covers not only how to attack but also how to build protection at the code and configuration level. Learning is text-based, with personalized lessons for your level, and detailed answers can be discussed in an AI chat.

Who this path suits and who it doesn't

Suits:
- Developers who want to write secure code and understand how their code can be attacked.
- Testers who need to go beyond functional testing.
- Administrators responsible for configuring servers and applications.

Doesn't suit:
- Those looking only for attacking techniques without protection — there are specialized pentest courses for that.
- Beginners without programming experience — basic understanding of SQL and HTTP will be required.
- Those expecting a certificate: the asibiont.com platform does not issue certificates.

In conclusion

Web security is not a list of vulnerabilities but a mindset. SQL injections remain at the top because protection requires discipline and understanding of mechanisms, not just installing a library. Mistakes in privilege configuration, error handling, and third-party dependencies can negate even correct queries.

If you want to systematically understand the OWASP Top 10 and learn to build protection, check out the course Web Security (OWASP Top 10). There you will find practical case studies and feedback on your solutions — without promises of certificates or magic pills.

You can start here: Web Security.