What is SQL Injection and How It Works?


What is SQL Injection and How It Works?

An SQL injection is basically a cyber attack on the security posture of an IT infrastructure which includes the insertion or injection of an SQL query through the varied input data from the customer to the app.  In addition, SQLi commands are sincerely inserted into a particular data-plane input that affects the carrying out of predefined SQL regimes.  After that, a successful SQL injection abuse can nicely read the crucial and sensitive types of information from the datasets and alter database datasets (like insert, update, or vanish), conduct administrative functions on the database, retrieve the content of a database management system file, and even give orders to the operating system in some models.

In case a web application or website utilizes SQLi databases such as Oracle, SQL Server, or MySQL, it is significantly powerless against an SQL injection attack.  In addition, hackers utilize SQL injection invasions to approach sensitive business or personally identifiable information (PII) that eventually enhances sensitive information.

What is SQL Injection Attack?

As described above and by mainstream cyber security specialists all over the world, SQL Injection Attacks are one of the most widespread among OWASP’s Top 10 Vulnerabilities and one of the ancient application vulnerabilities.  In this regard, one latest report lists it as the 3rd most common sensitive vulnerability.

Types of SQL Injection (SQLi)

SQLi or SQL injection attacks are very common these days to check out the vulnerabilities comprised in an IT infrastructure.  In general, there are two types of SQL injection attacks, such as the following:

  • Error Based SQL injection
  • Blind Based SQL injection

Error Based SQL Injection:

In Error based SQL Injection tactic, an adversary attempts to put some malicious code or query in the input slots and gets some significant error regarding SQL syntax or database.

For instance, SQL syntax errors should be like this:

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘‘VALUE’’.

This type of particular error message provides info about the database utilized, wherever the syntax error took place in the query.  In crisp words, Error based tactic is the most effortless way to find SQL Injection.

Blind SQLI

One can understand that by attempting to attack with the normal SQLi application pops out a casual error message depicting that syntax of the SQL query is vastly different or inaccurate.  However, Blind SQLi is a general type of SQL injection technique that functions by putting SQLi queries to the datasets blindly and identifying the response based on the modification in the behavior of the response.

In addition, Blind SQLi is generally not familiar with ERROR based, in which the user puts some SQL queries as opposed to the datasets where the corresponding users get a stated error message.  Moreover, the attacker attempts to get info by enquiring about the datasets’ genuine or fake query.  Hence, strictly based on the forecasting, we require to elaborate on the output.

It is further elaborated in 2 types:

  • Boolean based SQLI
  • Time-based SQLI

How SQL Injection works?

SQL injection generally happens when you question a user for input, such as their username/ user ID, and in spite of a name/ ID, the user provides you an SQL statement that you will unawarely run on your datasets.

As a general rule, an SQL Injection attack includes an introduction or injection of an SQL query through the client’s input datasets to the corresponding app.  In this regard, SQL injection coding commands are inserted into data-plane input that sincerely affects the execution of pre-described commands of an SQL query.

Moreover, this can be answered by several persons asking to know what is SQL injection and how it works.

SQL Injection Cheat Sheet

This SQL injection cheat sheet includes many primetime examples of helpful syntaxes, which one can sincerely utilize to carry out a bulk of operations that usually arise when executing SQL injection attacks.

One can understand to apply varied functions on several interfaces like Oracle, Microsoft, PostgreSQL, MySQL, etc.  In addition, some of the main functions that a person can perform using SQL Injections Commands are as follows:

  • String concatenation
  • Substring
  • Comments
  • Database version
  • Database contents
  • Conditional errors
  • Batched (or stacked) queries
  • Time delays
  • Conditional time delays
  • DNS lookup
  • DNS lookup with data exfiltration

SQL Injection or 1=1

As a general rule, SQL Injection Based on 1=1 is forever genuine.

Look at the example beneath once.


The prime objective of the given code is to establish an SQL query to choose a user with a given user id.

However, if there is none to secure a user from going “wrong” input, then the same user can go in some “smart” input like this:

UserId: 105 or 1 = 1

Ahead, the SQL statement would be something like the following:

In this regard, the SQL query above is truly legitimate and would definitely give back ALL rows from the corresponding “Users” table since OR 1 = 1 is forever genuine.

Now, let’s come to this verdict and ask a couple of questions!

Does the example above seem threatening?  What would be done if the “Users” table possessed names and passwords?

As a result, the SQL query above would be something like the following:

In a nutshell, an adversary might be able to possess some decent access to all the user names and passwords in datasets by merely inputting 105 OR 1=1 into the given slot.

Frequently Asked Questions

About What is SQL Injection and How It Works?

1: What is SQL Injection OWASP?

In general, an SQL injection attack is the sub-part of “Injection,” which is a vulnerability from the OWASP Top 10 Vulnerabilities system, as described on its official website.

2: What are the 3 major SQL operations?

The 3 major SQL Operations or commands are described as follows:

  • DDL (Data Definition Language),
  • DML (Data Manipulation Language), and
  • TCL (Transaction Control Language).

3: What are 5 types of SQL injection?

The main types of SQL injections are as follows:

  • Error Based SQL injection
  • Blind Based SQL injection
    • Boolean based SQLI
    • Time-based SQLI

4: What is an example of SQL injection?

The prime examples of SQL injection conclude calls to the operating system via a system call, the utilization of external programs through shell commands, or calls to the backend datasets utilizing SQL (i.e., SQL injection).

5: What does SQL injection means?

SQL injection is basically a string of code injection technique that is sincerely constructed to delete your databases.  In this regard, SQL injection is one of the most common web hacking tactics.  Moreover, SQL injection is the prime placement of malicious code in SQL queries through web page input.

6: Why do hackers use SQL injection?

SQLi or SQL injection attacks allow the working adversaries to spoof identity, interfere with the current datasets, causing rejection concerns, like eliminating transactions or altering balances, permitting the entire revelation of all data on the system, vanishing the entire data, or making it otherwise inaccessible, and become managers of the database server.

7: What are 3 methods SQL injection can be done by?

The SQL injections generally come under the purview of 3 methods, such as the following:

  • In-band SQLi (Classic),
  • Inferential SQLi (Blind), and
  • Out-of-band SQLi.

8: What are the 3 types of SQL commands?

The main 3 types of SQL Commands are as follows:

  • DDL (Data Definition Language) commands,
  • DML (Data Manipulation Language) commands, and
  • DCL (Data Control Language) commands.

9: What are the 4 parts of SQL?

The prime 4 parts of SQL query comprisethe following:

  • Data Query,
  • Data Manipulation (insert, update, and delete),
  • Data Definition (schema creation and modification), and
  • Data Access Control.


To wrap up, we tried to provide the best knowledge we have related to SQL Injections by every means.  In this regard, if anyone wishes to know more about the same topic, then the same person can opt for the world-class 1 Year Diploma in Cyber Security Course by Craw Security, the Best Cyber Security Institute in India, remarkably present in the NCT of Delhi from the past 10+ years offering international standard cyber security education to the interested candidates.

In addition to this, Craw Security’s courses are highly accredited to FutureSkills Prime, a MeitY — NASSCOM, Digital Skilling Initiative.

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