20 SQL Injection Interview Questions and Answers

SQL Injection is a type of code injection attack where an attacker inserts malicious code into an SQL statement via user input. This can be done in order to manipulate the database and gain access to sensitive information. If you are interviewing for a position that involves working with databases, it is important to be familiar with SQL Injection and be able to answer questions about it. In this article, we will discuss some common SQL Injection interview questions and how you should answer them.

SQL Injection Interview Questions and Answers

Here are 20 commonly asked SQL Injection interview questions and answers to prepare you for your interview:

1. What is SQL Injection?

SQL Injection is a type of attack where a malicious user is able to execute unauthorized SQL commands by exploiting a vulnerability in a web application. This can be done in order to gain access to sensitive data, or to modify data in the database. In order to prevent SQL Injection attacks, it is important to use parameterized queries and to sanitize user input.

2. Can you give me an example of how a hacker could use SQL injection to gain unauthorized access?

One example of how a hacker could use SQL injection to gain unauthorized access is by inputting malicious code into a form field that is then used to generate a SQL query. If the code is executed, it could allow the hacker to view sensitive information or even make changes to the database.

3. What are some common tools used by hackers when attempting to execute a SQL injection attack?

Some common tools used by hackers when attempting to execute a SQL injection attack include:

-SQLMAP: This is a tool that can automatically detect and exploit SQL injection vulnerabilities.

-Havij: This is a tool that can be used to exploit SQL injection vulnerabilities in order to take over a database.

-SQLninja: This is a tool that can be used to exploit SQL injection vulnerabilities in order to take over a web server.

4. How can I prevent SQL injection attacks on my website?

The best way to prevent SQL injection attacks is to use parameterized queries. This means that instead of concatenating user input directly into your SQL code, you instead use placeholders and then supply the user input as a separate parameter. This way, even if the user input is malicious, it will not be able to interfere with the rest of your SQL code.

5. Why do you think the “like” operator is so dangerous in the context of SQL injection?

The “like” operator is dangerous in the context of SQL injection because it allows an attacker to input SQL code that can be executed by the database. This can be used to bypass security controls, view sensitive data, or even delete data.

6. Is it possible for a single SQL query to cause multiple vulnerabilities within a database? If yes, then please explain with an example.

Yes, it is possible for a single SQL query to cause multiple vulnerabilities within a database. For example, if a user input is not properly sanitized, then it could allow an attacker to insert malicious SQL code into the query that could delete data from the database, or even allow the attacker to gain access to sensitive information.

7. How does SQL injection work?

SQL injection is a type of attack where a malicious user is able to execute malicious SQL code on a database. This can be done in a number of ways, but the most common is by inputting malicious SQL code into a web form that is then executed by the database.

8. Why do you think parametrized queries mitigate the risk of SQL injection?

Parametrized queries help to mitigate the risk of SQL injection because they allow you to specify exactly what data you are looking for, and they prevent outside input from being able to change the structure of the query. This means that even if someone tries to inject malicious input into your query, it will not be able to change the query itself, and therefore will not be able to cause any harm.

9. What is Union-based SQL injection? Can you describe what happens during this type of attack?

Union-based SQL injection is a type of attack where the attacker takes advantage of the UNION SQL operator to combine the results of two or more SQL queries into a single result. This can be used to bypass security restrictions or to retrieve data that the attacker would not normally have access to. To perform a union-based SQL injection attack, the attacker will first need to find a vulnerable SQL query that uses the UNION operator. They will then craft a second SQL query that they inject into the first query. The results of both queries will be combined and returned to the attacker.

10. How do you know if a parameterized query has been created correctly?

There are a few things you can look for to ensure that a parameterized query has been created correctly. First, all parameters should be replaced with placeholders (usually represented by a question mark). Second, the parameters should be passed in as separate arguments, rather than being concatenated into the SQL query string. Finally, the data type of the parameters should be checked to ensure that they match the expected data type for the corresponding database columns.

11. Are there any other ways to mitigate against malicious SQL injection attempts besides using prepared statements and stored procedures?

There are a few other ways to help mitigate against SQL injection attacks, including:

– Escaping all user input: This ensures that any potentially malicious input is treated as a string literal instead of as code.
– Using a whitelist of accepted input: This can help to ensure that only expected and safe input is processed by your application.
– Limiting user privileges: This can help to prevent users from being able to execute potentially harmful SQL queries, even if they are able to inject malicious input into your application.

12. What is Boolean-based SQL injection? Can you describe what happens during this type of attack?

Boolean-based SQL injection is a type of attack where the attacker inserts malicious code into an SQL statement in order to change the statement’s meaning and cause it to return unexpected or unwanted results. This type of attack can be used to bypass security controls, access sensitive data, or even delete data.

13. What is Error-base SQL injection? Can you describe what happens during this type of attack?

Error-based SQL injection is a type of attack where the attacker attempts to inject malicious SQL code into a web application in order to cause an error. This type of attack can be used to gain access to sensitive information, such as passwords or credit card numbers.

14. What is Time-based SQL injection? Can you describe what happens during this type of attack?

Time-based SQL injection is a type of attack where the attacker sends malicious SQL queries to the database and then measures the time it takes for the database to respond. If the database responds slowly, then the attacker knows that the query was successful and can use that information to extract data from the database.

15. What’s the difference between content-based and non-content based SQL injection?

Content-based SQL injection attacks focus on the data within the database, while non-content based SQL injection attacks focus on the structure of the database itself. In a content-based attack, the attacker is looking to extract or modify data within the database. In a non-content based attack, the attacker is looking to drop tables or otherwise damage the structure of the database.

16. How would you test for SQL injection vulnerabilities?

There are a few ways to test for SQL injection vulnerabilities. One way is to simply try to input SQL code into web form fields and see if the code is executed. Another way is to use a tool like SQLMap to automate the process of testing for SQL injection vulnerabilities.

17. What is your understanding of code obfuscation as it relates to SQL injection?

Code obfuscation is a technique used to make code more difficult to read or understand. This can make it more difficult for someone to find and exploit vulnerabilities in the code. In the context of SQL injection, code obfuscation can make it more difficult for an attacker to insert malicious SQL code into a database query.

18. What do you understand about blind SQL injection?

Blind SQL injection is a type of attack where the attacker is able to execute SQL commands on a database without being able to see the results of those commands. This can be done by carefully crafting SQL queries that cause the database to return error messages that reveal information about the structure of the database or the data that is stored in it.

19. Have you ever heard of a web service or interface that was vulnerable to a SQL injection attack? Please describe what happened.

Yes, I have heard of a web service or interface that was vulnerable to a SQL injection attack. In this case, an attacker was able to insert malicious SQL code into a web form input field. This code was then executed by the web server, which allowed the attacker to gain access to sensitive data stored in the database.

20. What is your opinion on NoSQL databases? Do you think they’re less vulnerable to SQL injection than traditional relational databases?

I believe that NoSQL databases have their own set of vulnerabilities, but I don’t think that SQL injection is one of them. In fact, I think that NoSQL databases may be less vulnerable to SQL injection because they don’t use the same kind of query language that relational databases do. With NoSQL databases, you’re more likely to use something like JavaScript, which is less susceptible to SQL injection attacks.