Why SQL security awareness matters - Challenge Your Understanding

Challenge - 5 Problems

🧠 Conceptual

intermediate

Why is SQL injection a serious security risk?

Imagine a website where users enter their username and password. If the website's database queries are not secure, what can happen if someone uses SQL injection?

A The database will delete itself to prevent attacks.

B The website will automatically block the attacker without any damage.

C The attacker can only see public information, no harm done.

D The attacker can access or modify data they shouldn't be able to see.

💡 Hint

Think about what happens when user input is treated as code.

SQL injection allows attackers to run harmful commands on the database, leading to unauthorized data access or changes.

❓ query_result

intermediate

What happens if user input is not sanitized in this query?

Consider this SQL query used in a login system:

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

If a user inputs ' OR '1'='1' -- as username and anything as password, what will the query return?

A It returns all users because the condition always becomes true.

B It returns no users because the syntax is invalid.

C It returns only the user with username ' OR '1'='1.

D It causes the database to crash.

💡 Hint

Look at how the OR condition affects the WHERE clause.

The injected OR condition makes the WHERE clause always true, so all rows are returned, bypassing login checks.

📝 Syntax

advanced

Identify the syntax error in this SQL command

Find the syntax error in the following SQL statement:

INSERT INTO users (username, password VALUES ('alice', 'pass123');

A Missing closing parenthesis after column names.

B Incorrect keyword 'VALUES' used.

C Missing comma between values.

D Quotes around values are not allowed.

💡 Hint

Check the parentheses around the column list.

The opening parenthesis after column names is not closed before VALUES keyword, causing syntax error.

❓ optimization

advanced

Which index improves security and performance for user login?

You have a users table with columns: id, username, password_hash, email.

To speed up login checks and prevent unauthorized data access, which index is best to create?

A CREATE INDEX idx_password ON users(password_hash);

B CREATE INDEX idx_username ON users(username);

C CREATE INDEX idx_email ON users(email);

D CREATE INDEX idx_id ON users(id);

💡 Hint

Think about which column is used to find users during login.

Indexing username speeds up lookups and helps enforce uniqueness, reducing risk of unauthorized access.

🔧 Debug

expert

Why does this SQL query expose sensitive data?

Given this query:

SELECT username, password FROM users WHERE active = 1;

Why is this a security risk?

A It lacks a LIMIT clause, causing performance issues.

B It filters only active users, so no risk exists.

C It exposes password hashes which should be kept secret.

D It uses SELECT instead of DELETE, causing data leaks.

💡 Hint

Consider what data should never be exposed in queries.

Passwords or their hashes should never be returned in queries to prevent attackers from stealing them.