SQL is a query language developed for managing data in relational databases. It allows you to view, change, and delete data. Many web apps and websites use SQL databases to store all of their data. You may also use SQL commands to run operating system commands in some situations. As a result, a good SQL Injection attack can have serious ramifications.
An attacker must first identify weak user inputs inside the web page or web application before launching a SQL Injection attack. An SQL Injection vulnerability affects a web page or web application that uses user feedback directly in a SQL query. The intruder can generate input material. This type of content is known as a malicious payload, and it is an important part of the attack. Malicious SQL commands are executed in the database after the attacker sends this content.
Also Read: What is a Cyber Attack?
What is SQL Injection?
SQL injection is a common hacking technique that can trigger major issues within a company. An attacker can easily get around security measures like authentication by using SQL injection.
SQL Injection can be used to trigger serious issues in a variety of ways. An intruder may use SQL Injection to bypass authentication. It gains access to, alter, and deletes data in a database.
SQL Injection can be used to execute commands on the operating system in some cases. It allows an attacker to escalate to more damaging attacks within a network protected by a firewall.
Types of SQL Injection in Cyber Attack
Here in this section, we will discuss the “Type of SQL Injection in Cyber Attack”. In-band SQLi, inferential SQLi, and out-of-band SQLi are the three main types of SQL injection in cyber attack.
1. In-band SQLi (Classic SQLi)
The most popular and easy-to-exploit SQL Injection attack is in-band SQL Injection. Here an attacker is able to execute the attack. It can also collect the results using the same communication channel.
Error-based SQL injection and Union-based SQL injection are the two most popular forms of it.
Error-based SQLi: This technique uses the database server’s error messages to collect knowledge about the database’s structure. An attacker may often enumerate an entire database using only error-based SQL injection. Although errors are useful during the creation process of a web application, they should be disabled on a live site or logged to a secure file.
Union-based SQLi: This technique uses the UNION SQL operator to combine the results of two or more SELECT statements into a single output. It is then returned as part of the HTTP response.
2. Inferential SQLi (Blind SQLi)
Unlike in-band SQLi, inferential SQL Injection takes longer for an attacker to manipulate. It is, however, just as dangerous as any other SQL Injection process. No data is actually transmitted through the web application in an inferential SQLi attack.
The attacker cannot see the outcome of an attack in-band. That is why such attacks are widely referred to as “blind SQL Injection attacks”.
Instead, by sending payloads, monitoring the web application’s response, and the database server’s subsequent actions, an attacker can recreate the database structure.
Blind-boolean-based SQLi and Blind-time-based SQLi are the two forms of inferential SQL injection.
Boolean-based (content-based) Blind SQLi: It is an inferential SQL Injection technique that uses a SQL query to compel the application to return a different answer depending on whether the query returns TRUE or FALSE.
The content of the HTTP answer will alter or stay the same depending on the outcome. Even if no data from the database is retrieved, an attacker may assume whether the payload used returned true or false. Since an attacker will have to enumerate a database character by character, this attack is usually slow (especially on large databases).
Time-based Blind SQLi: It is an inferential SQL Injection technique that uses a SQL query to force the database. It waits for a set amount of time (in seconds) before responding. The attacker would be able to tell whether the question result is TRUE or FALSE based on the response time.
An HTTP response will be returned with a pause or instantly, depending on the outcome. Even if no data from the database is retrieved, an attacker may assume whether the payload used returned true or false. Since an attacker will have to enumerate a database character by character, this attack is usually slow (especially on large databases).
3. Out-of-band SQLi
It is uncommon, relies on functionality being available on the database server that the web application uses. When an intruder is unable to launch and gather data through the same channel, out-of-band SQL Injection occurs.
Out-of-band techniques give an attacker a better option than inferential time-based techniques, particularly if server responses aren’t always consistent (making an inferential time-based attack unreliable).
This technique will depend on the database server’s ability to send data to an attacker via DNS or HTTP requests. Such is the case with the xp dirtree command in Microsoft SQL Server.
It can be used to send DNS requests to a server controlled by an attacker. The UTL HTTP package in Oracle Database, which can be used to send HTTP requests from SQL and PL/SQL to a server controlled by an attacker.
Input validation and parameterized queries, including prepared statements, are the only surefire ways to avoid SQL Injection attacks. The input should never be used explicitly by the application code. All input, not just web form inputs like login forms, must be sanitized by the developer. Single quotes, for example, are potentially malicious code elements that must be removed. On your production sites, it’s also a smart idea to toggle off the visibility of database errors. SQL Injection can be used to obtain knowledge about the database by exploiting database errors.