Error-based SQL injection

SQL injection is a type of web application attack that allows attackers to inject malicious SQL statements into the application's backend database, leading to unauthorized access or modification of data. One type of SQL injection attack is error-based SQL injection, which exploits error messages generated by the application to extract sensitive information.

Where is the attack used:

Error-based SQL injection attacks are commonly used in web applications that are vulnerable to SQL injection attacks. These vulnerabilities can be introduced through poor coding practices, such as using dynamic SQL queries with user input, or failing to sanitize user input.

Why use this attack:

Attackers use error-based SQL injection attacks to extract sensitive information from the application's database, such as usernames, passwords, and credit card numbers. They can also use this attack to gain unauthorized access to the application's backend systems, such as the server's operating system.

Method of attacks:

In an error-based SQL injection attack, the attacker injects a malicious SQL statement into the application's input field, causing the application to generate an error message. The error message contains valuable information about the application's database structure and the data contained within it. The attacker then uses this information to refine their attack and extract sensitive data.

How to secure from this attack:

To secure your web application from error-based SQL injection attacks, you should use parameterized queries and stored procedures instead of dynamic SQL queries with user input. You should also sanitize user input to prevent the injection of malicious SQL statements.

Types of error-based SQL injection:

There are two types of error-based SQL injection attacks: boolean-based and time-based.

1. Boolean-based: In a boolean-based error-based SQL injection attack, the attacker uses boolean operators to exploit the application's response to true or false conditions. The attacker injects a malicious SQL statement that evaluates to true or false, causing the application to generate an error message with valuable information.

2. Time-based: In a time-based error-based SQL injection attack, the attacker uses a delay function to exploit the application's response time. The attacker injects a malicious SQL statement that causes the application to delay its response time, allowing the attacker to extract sensitive information based on the delay time.

Example 1: Boolean-based error-based SQL injection attack

Suppose a web application has a search feature that allows users to search for products by name. The application uses the following SQL query to retrieve the product information:

example
SELECT * FROM products WHERE name = '$name';

An attacker can inject a malicious SQL statement into the search field to extract sensitive information:

example
' OR 1=1 UNION SELECT username, password FROM users WHERE '1'='1

This statement causes the application to generate an error message with the usernames and passwords of all users in the database.

Example 2: Time-based error-based SQL injection attack

Suppose a web application has a login feature that allows users to log in using their username and password. The application uses the following SQL query to verify the user's credentials:

example
SELECT * FROM users WHERE username = '$username' AND password = '$password';

An attacker can inject a malicious SQL statement into the username field to extract sensitive information:

example
' OR 1=1; SELECT pg_sleep(5)--

This statement causes the application to delay its response time by 5 seconds, indicating to the attacker that the injection was successful. The attacker can then refine their attack to extract sensitive information from the database.

Consultation:

If you are concerned about error-based SQL injection attacks on your web application, you should consult with a security expert or penetration tester to identify vulnerabilities and implement security measures to protect your application. Additionally, you should keep your software up-to-date and apply patches and security updates as soon as they become available.