SQL injection attacks are a type of code injection technique that exploit the use of dynamic SQL queries in web applications. Attackers can inject malicious SQL statements into user input fields, such as login forms, search boxes, or URLs, and execute them on the underlying database. This can result in unauthorized access, data theft, data corruption, or denial of service.

To prevent SQL injection attacks, web developers should use the following techniques:

Use prepared statements and parameterized queries: Prepared statements are SQL queries that are precompiled and executed with user-supplied parameters. Parameterized queries are SQL queries that use placeholders for user input and bind them to actual values at runtime. Both techniques separate the SQL code from the user input, making it impossible for attackers to inject SQL commands into the query. For example, in Java, PreparedStatement is a class that implements parameterized queries. In PHP, PDO and mysqli are extensions that support prepared statements.

Block SQL code execution in the web application database login: Web applications should use a dedicated database user account with limited privileges to connect to the database. This account should only have the permissions necessary to perform the required operations, such as select, insert, update, or delete. It should not have the permissions to execute arbitrary SQL commands, such as create, drop, alter, grant, or revoke. This way, even if an attacker manages to inject SQL code into the query, the database will reject it due to insufficient privileges.