SQL injection also referred to as SQLi is one of the prevalent threats in informatisation on the Internet, which allows for the injection of the sent SQL-command. An SQL injection attack may lead to another level of control of the system and even alteration of information contained within a system.
This article covers what SQL injection is, the types of SQLi, illustration of the difference between the attacks; and the ways of eradicating the attacks.
Table of Contents
What is SQL Injection?
SQL injection is simply a kind of attack that is directed towards an application with a view of inserting a piece of SQL code into any input field in order to gain access to restricted information in the database. These include cases where user inputs are not validated in a way that checks whether the data that is being entered into the database are the correct ones or not; this allows hackers to either input the wrong data into the database or delete the right data.
An example of a vulnerable principle includes allowing input from users into the application and then inputting the entered input straight to the SQL query without protection. This allows hackers to:
- Read, write, or delete records in an organized list
- Hack and try to enter a restricted area
- Perform tasks that concern the administration of the database service.
- Type customers’ details such as password accounts and other information explicitly.
Types of SQL Injection Attacks
There are several types of SQL injection attacks, each with unique techniques and impacts.
1. Classic SQL Injection
This is the most basic method of the attack where the attackers include additional SQL statements in the actual queries. It is used widely for avoiding the forms to login and extract the necessary information.
2. Blind SQL Injection
In this type of attack, the attacker does not know the result of the injections made on the database side. Instead, they discuss the flow of the execution to deduce database contents.
It shows the correctness of the condition, which helps the attacker obtain indirect data exchange.
3. Time-Based SQL Injection
This involves using SQL queries which are designed to either cause intentional delays in the entire response time of the database. By calculating the response time, an attacker could determine if an injected query was run at all. Though the attacker may not know the exact time taken by the server in responding, if the server takes longer time, the attacker is sure that the injection has been successful.
4. Error-Based SQL Injection
This method involves creating a dictionary of common errors returned from a database to probe out the extra data. This often involves entering predictive SQL queries that prompt the database into returning an error message which contains important information of the database structure. When the application returns an error message stating an invalid column index, one should have an induced clue about the schema of the database.
5. Union-Based SQL Injection
Data is obtained in method of union-based SQL injection by executing additional operations with the help of UNION. This enables attackers to query the database in order to select information from various tables within the database.
How to Prevent SQL Injection Attacks
1. Use Prepared Statements and Parameterized Queries
The best way that can be used to avoid it is through the use of prepared statements and parameterized queries. These ensure that what the user inputs are not interpreted as command codes for SQL or some other language. The query parameters are manipulated as data and therewith the attack of malicious SQL commands are not possible.
2. Use Stored Procedures
Stored procedures are precompiled that do not allow dynamic query execution that is a cause of SQL injection/misfortune. Through stored procedures, developers cut out the possibility of anyone to input something into SQL queries hence preventing it.
3. Validate and Sanitize User Inputs
It is necessity to check incoming entries to derive values from them always and only expect certain data to be entered. Whitelisting techniques will exclude all the unwanted characters from the list except the specific ones permitted.
4. Limit Database Privileges
The database has additional user and group privileges that may make unauthorized changes, such as executing malicious queries that could lead to potential harm. There is a common mistake where people use either the root or the admin account to access a database, and this should not be done.
5. Disable Detailed Error Messages
Compiler-generated error messages should not contain database details as a way of escalating the attack by the attackers. However, in such a case, the function should return an unspecified error message.
6. Implement a Web Application Firewall (WAF)
A WAF is a security device that can be used effectively for real time detection and blocking of it. Some of the good SQL injection protection service providers are Cloudflare, AWS WAF and Imperva.
Final Thoughts
SQL injection is still an important, and widely used type of attack. To mitigate this type of attack, organizations need to provide protection to its databases using proper input validation and implementing access control mechanisms as well as using prepared statements.
To prevent SQL injection, equip yourself with the necessary knowledge, follow the guidelines provided in this article, and make sure no hacker compromises your personal and business information.
Also Read: What is Spoofing in Cybersecurity? Types, Examples & Prevention