If you're not familiar with SQL injection, now is a good time to learn about it. In this article, we'll explain what SQL injection is, how it works, some of its techniques, and how you can protect your applications from it. We'll also take a look at some real-world examples of SQL injection attacks. So if you're interested in learning more about this dangerous vulnerability, keep reading!
SQL stands for Structured Query Language which is a language that allows users to interact with and change data in a database. The official standard for SQL was created by the American National Standards Institution (ANSI). SQL statements can be used to retrieve data from a database table or perform changes to existing tables. It is commonly used in many web applications to add, delete, modify and display data.
Examples of SQL commands:
SELECT * FROM TestTable WHERE Name = 'John' AND BirthDate < CURRENT_DATE; --Returns all rows from table test table where name equals john and birthdate is less than today's date
UPDATE Students SET Enrollment_Date = Date(15, 8, 2015) WHERE StudentID = 3; -- Changes the enrollment date of student 3 to August 15th, 2015
DELETE FROM Students WHERE StudentID IN (1, 2); -- Deletes all student informations with studentID of 1 and 2.
SQL Injection is one of the most common vulnerabilities on a web application. It was included in Injection, the most common web vulnerability in the first line of OWASP 2017:Top 10. And, it still remains as one of the most common vulnerabilities in the 3rd line after four years, in OWASP Top10:2021 Vulnerabilities. This happens when an attacker injects malicious SQL query into input fields on a web page in order to execute unintended SQL commands.
A common way to gain unauthorized access to web applications is by exploiting SQL injection vulnerabilities. SQL Injection still occurs because of the mistakes that are made by the developers. An attacker, who realizes an SQL injection, can trigger much more dangerous vulnerabilities like remote code execution using SQL injection.
When websites don't properly validate user inputs before passing it along to backend databases, hackers can supply malicious code via input fields for interaction with other users' sensitive information, such as login credentials. This allows attackers who successfully carry out SQL injections to gain full control over poorly protected databases and their data including credit card information, usernames and passwords, etc.
Attackers primarily take advantage of SQL injections to alter existing SQL queries that are executed by a web application against a database server in order to either extract or modify sensitive SQL data. This is done through the SQL-client/SQL-server software by sending crafted SQL statements via malicious client requests to the SQL-server instance. Attackers can do this by injecting SQL injection code into input fields. When the SQL statements are passed from the client side app through these entry fields and sent back to backend databases for parsing, any injected SQL commands will be parsed together with these legitimate ones, resulting in non-intended behavior of the backend dbms.
Generally, SQL injection attacks can be used to gain unauthorized access to SQL databases, execute SQL statements on behalf of the authenticated users or even delete records in SQL databases.
There are several subcategories of SQL injection according to their triggering techniques that attackers use to exploit SQL vulnerabilities in applications and websites including boolean-based blind SQL injection, time-based blind SQL injection, error-based SQL injection and union based SQL injection,etc.
To avoid SQL injections, you should check your systems regularly. To do it, you can scan your applications using our most common SQL Injection Vulnerability Scanner for free:
SQL Injection might occur in various applications and we cover most of them in our set of SQL Injection Scanning Tools. You can scan for vulnerabilities according to your application using the appropriate one for your application in specific. Please let us know if you think we don’t have the one you’re looking for so we can offer that for you, too!
According to scan’s output, if any vulnerability is found, you should use parameterized queries (prepared statements) for all interactive communication with SQL databases. Connection strings provided via configuration files or other means must only accept valid input parameters that are included in the list of expected values; all other input is rejected as malformed(white-listing). In addition, while making a database connection, the principle of least privileges should be applied. The connection shouldn’t be provided by giving unlimited access to the unnecessary places.
So, if you're not sure what SQL injection is or how it works, now's the time to find out. Even though OWASP has been reporting on this vulnerability for quite some time and many people are aware of its dangers, there are still plenty who have never heard about it before. If your web application needs protection from SQL injections, request a pentest from our cybersecurity experts today!