Structured Query Language (SQL) Injection

SQL injection is a type of security vulnerability that occurs when an attacker manipulates input data to execute malicious SQL (Structured Query Language) statements within an application's database. It takes advantage of improper input sanitization or insufficient validation, allowing the attacker to modify or retrieve unauthorized data, modify database structure, or execute arbitrary commands.

The steps involved in a typical SQL injection attack are as follows:

1. Input Point: The attacker identifies an input point in the application that directly or indirectly interacts with the database. This can be a form field, URL parameter, or any other user-supplied input.
2. Malicious Input: The attacker crafts a malicious input containing specially crafted SQL syntax, such as additional SQL statements, comment characters, or logical operators.
3. Injection Point: The attacker injects the malicious input into the vulnerable input point, causing the application to unknowingly execute the injected SQL code within the database.
4. Unauthorized Actions: The injected SQL code can result in various unauthorized actions, such as data extraction, modification, or deletion, bypassing authentication mechanisms, or even gaining remote command execution on the database server.

To mitigate SQL injection attacks, the following preventive measures can be implemented:

• Parameterized Queries: Use parameterized or prepared statements with placeholders to separate the SQL code from user-supplied input. This ensures that user input is treated as data, preventing the possibility of SQL injection.
• Input Validation and Sanitization: Implement strict input validation and sanitization routines to filter out or escape any potentially malicious input. This includes rejecting or encoding special characters that could alter the SQL syntax.
• Least Privilege Principle: Ensure that the database user accounts used by the application have limited privileges necessary for their intended tasks. Avoid using privileged accounts with broad permissions that could amplify the impact of a successful SQL injection attack.
• Secure Coding Practices: Follow secure coding practices, such as avoiding the dynamic construction of SQL queries with user input, using ORM (Object-Relational Mapping) frameworks, and utilizing input validation libraries to handle user input securely.