SQL injection

 In GCSE Computer Science, SQL injection is a type of cyber attack where malicious code is inserted into SQL queries to manipulate or access a database without authorization. It exploits vulnerabilities in how web applications handle user input when constructing database queries. 

Here's a more detailed explanation:

What is SQL?

SQL (Structured Query Language) is a programming language used to manage and manipulate databases. 

How it works:

When a user enters information into a website (like a login form), that input is often used to build an SQL query to retrieve or modify data in a database. An attacker can exploit this by injecting malicious SQL code into the input field, which the application then includes in its query. 

Example:

Imagine a website that allows users to log in by entering their username and password, which are then used in an SQL query like this: SELECT * FROM users WHERE username = '{username}' AND password = '{password}';. An attacker could enter " or "1"="1 as the password, which would make the query look like SELECT * FROM users WHERE username = 'user123' AND password = '' OR '1'='1';. Since '1' always equals '1', this query would return all user records, effectively bypassing the login process. 

Consequences:

SQL injection attacks can have serious consequences, including:

Data Breaches: Allowing attackers to view, modify, or delete sensitive data from the database. 

Bypassing Authentication: As in the example above, attackers can gain unauthorized access to accounts. 

System Compromise: In some cases, attackers can even gain control of the entire database server. 

Prevention:

To prevent SQL injection attacks, developers should:

Input Validation: Validate all user input to ensure it conforms to expected formats and does not contain malicious code. 

Parameterized Queries (Prepared Statements): Use parameterized queries or prepared statements, which treat user input as data rather than code, preventing injection. 

Principle of Least Privilege: Limit database user permissions to the minimum required for the application's functionality.