SQL injection testing in Testing Fundamentals - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is SQL Injection?

SQL Injection is a security vulnerability where an attacker inserts malicious SQL code into input fields to manipulate the database.

beginner

Why is SQL Injection testing important?

It helps find weaknesses in applications that could allow attackers to access or damage data, protecting user information and system integrity.

beginner

Name a common method to test for SQL Injection.

Entering special characters like ' or " or SQL keywords such as OR 1=1 in input fields to see if the application behaves unexpectedly.

intermediate

What is a parameterized query and how does it help prevent SQL Injection?

A parameterized query separates SQL code from data inputs, so user inputs are treated only as data, not executable code, preventing injection.

intermediate

What is the difference between error-based and blind SQL Injection testing?

Error-based testing looks for database error messages to find vulnerabilities, while blind testing infers vulnerabilities by observing application behavior without error messages.

Which input is commonly used to test for SQL Injection?

A 12345

B Hello World

C ' OR '1'='1

D <script>alert('test')</script>

The input ' OR '1'='1 is a classic SQL Injection test string that can manipulate SQL queries.

What does a parameterized query do?

A Combines user input directly into SQL code

B Separates SQL code from user input

C Encrypts the database

D Deletes user input before processing

Parameterized queries keep SQL code and user input separate to prevent injection attacks.

Which of these is NOT a sign of SQL Injection vulnerability?

A Unexpected database errors shown to users

B Application crashes on special input

C Data leakage through error messages

D Application ignores all user input

Ignoring all user input is not a sign of SQL Injection vulnerability.

Blind SQL Injection testing relies on:

A Application behavior changes without errors

B Network traffic analysis

C User interface design

D Database error messages

Blind SQL Injection tests infer vulnerabilities by observing changes in application behavior without error messages.

Which practice helps prevent SQL Injection?

A Validating and sanitizing user inputs

B Using dynamic SQL with string concatenation

C Displaying detailed database errors to users

D Allowing all user inputs without checks

Validating and sanitizing inputs helps prevent malicious SQL code from being executed.

Explain what SQL Injection is and why it is a security risk.

Think about how user input can change database commands.

Describe two methods to test for SQL Injection vulnerabilities.

Consider how you might check if an application is vulnerable without causing harm.

Practice

1. What is the main goal of SQL injection testing in software testing?

easy

A. To check if user input can change database queries and cause harm

B. To improve the speed of SQL queries

C. To test the user interface design

D. To verify the database schema structure

Solution

1. Step 1: Understand SQL injection testing purpose

   SQL injection testing checks if user inputs can alter SQL queries in harmful ways.

2. Step 2: Compare options with testing goal

   Only To check if user input can change database queries and cause harm matches the goal of detecting harmful input effects on queries.

3. Final Answer:

   To check if user input can change database queries and cause harm -> Option A

4. Quick Check:

   SQL injection testing = check harmful input [OK]

Hint: Focus on input impact on queries, not UI or speed [OK]

Common Mistakes:

• Confusing SQL injection testing with performance testing
• Thinking it tests UI or database design
• Ignoring the role of user input in testing

2. Which of the following is a correct example of an input used in SQL injection testing?

easy

A. DROP TABLE users;

B. SELECT * FROM users

C. INSERT INTO users VALUES ('admin')

D. ' OR '1'='1

Solution

1. Step 1: Identify typical SQL injection input

   Inputs like ' OR '1'='1 try to change query logic to always true.

2. Step 2: Check other options

   Options A, B, and D are full SQL commands, not typical injection inputs entered by users.

3. Final Answer:

   ' OR '1'='1 -> Option D

4. Quick Check:

   Injection input = ' OR '1'='1 [OK]

Hint: Look for input that changes query logic with OR and quotes [OK]

Common Mistakes:

• Choosing full SQL commands as injection input
• Not recognizing the use of quotes and OR in injection
• Confusing injection input with SQL statements

3. Consider this SQL query in a login system:

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

If the input for username is admin and for password is ' OR '1'='1, what will happen?

medium

A. The query will return no results

B. The query will cause a syntax error

C. The query will return all users, bypassing password check

D. The query will only return the admin user

Solution

1. Step 1: Substitute inputs into query

   The query becomes: SELECT * FROM users WHERE username = 'admin' AND password = '' OR '1'='1';

2. Step 2: Analyze the WHERE clause logic

   The OR '1'='1' makes the password condition always true, so the query returns all users matching username or always true condition.

3. Final Answer:

   The query will return all users, bypassing password check -> Option C

4. Quick Check:

   Injection bypasses password = returns all users [OK]

Hint: OR '1'='1' makes condition always true, bypassing checks [OK]

Common Mistakes:

• Ignoring OR logic and thinking password check still applies
• Assuming syntax error without checking quotes
• Thinking only admin user is returned

4. You have this vulnerable SQL query:

query = "SELECT * FROM products WHERE id = '" + user_input + "'";

Which fix will prevent SQL injection?

medium

A. Add more single quotes around user_input

B. Use parameterized queries or prepared statements

C. Remove the WHERE clause

D. Convert user_input to uppercase

Solution

1. Step 1: Identify the vulnerability

   Concatenating user input directly into query allows injection.

2. Step 2: Choose the correct fix

   Using parameterized queries safely separates input from code, preventing injection.

3. Final Answer:

   Use parameterized queries or prepared statements -> Option B

4. Quick Check:

   Parameterized queries prevent injection [OK]

Hint: Never concatenate input; use parameters instead [OK]

Common Mistakes:

• Thinking adding quotes fixes injection
• Removing WHERE clause breaks functionality
• Changing case does not prevent injection

5. A web app uses this query to search users:

SELECT * FROM users WHERE name LIKE '%{input}%';

Which input is the safest to test for SQL injection without causing errors or data loss?

hard

A. normaluser

B. admin'; DROP TABLE users;--

C. '; EXEC xp_cmdshell('dir');--

D. ' OR '1'='1

Solution

1. Step 1: Understand safe testing input

   Safe input should not break query syntax or cause harmful commands.

2. Step 2: Evaluate options

   Options A, B, and C contain injection attempts or dangerous commands; only D is a normal string safe for testing.

3. Final Answer:

   normaluser -> Option A

4. Quick Check:

   Safe test input = normaluser [OK]

Hint: Use normal strings to test safely before injection attempts [OK]

Common Mistakes:

• Using dangerous inputs that cause errors or data loss
• Assuming all injection inputs are safe to test
• Not understanding query context with LIKE and wildcards