15 Minutes a Day! – Lesson 117 – “Hacking Websites with SQL Injection”

Today’s lesson goal: Understand the basics of SQL injection, its impact on websites, and methods of prevention.

Introduction to SQL Injection

SQL injection is a code injection technique that exploits a security vulnerability occurring in the database layer of an application. The vulnerability is present when user inputs are not correctly checked within web applications. Hackers use this weakness to gain unauthorized access to data, such as customer information, personal details, trade secrets, and more.

How SQL Injection Works

1. User Input as Part of the Query: In a vulnerable website, user inputs are directly used in SQL queries. For example, a login form might directly include the username and password entered by the user in the SQL query to check the database.
2. Manipulating Queries: An attacker can manipulate these inputs to alter the SQL query and perform unauthorized actions. For example, adding a ' OR '1'='1 to a username input might result in the SQL query SELECT * FROM users WHERE username = '' OR '1'='1' which always returns true, thus bypassing authentication.
3. Extracting Data: By modifying queries, an attacker can extract sensitive data, delete data, or even gain administrative rights on the database.

Examples of SQL Injection Attacks

• Bypassing login screens.
• Accessing hidden data, such as personal user information.
• Modifying or deleting data in the database.
• Executing admin operations on the database, like shutting it down.

Preventing SQL Injection

1. Use Prepared Statements (Parameterized Queries): They ensure that an attacker cannot change the intent of a query, even if SQL commands are inserted by an attacker.
2. Use Stored Procedures: They separate the data from the code, making it harder for attackers to manipulate queries.
3. Input Validation: Ensure that only properly formed data is entering the system.
4. Escaping All User-Supplied Input: This can prevent attackers from changing the nature of a query.
5. Regular Security Testing: Regularly test web applications for vulnerabilities.

Why It’s a Serious Threat

SQL injection can lead to:

• Unauthorized viewing of user lists.
• Access to sensitive company data.
• Deleting data, causing irreparable loss.
• Website defacement.

In conclusion, SQL injection poses a severe threat to web application security. Awareness, proper coding practices, and regular testing are key to preventing these attacks.

Enhancing Your Learning

• Watch this video on SQL injection for a more in-depth understanding.
• Explore the OWASP guide on SQL Injection for detailed prevention techniques.