Web Pentesting Manual SQL Injection

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Web Pentesting Manual SQL Injection

SQL injection is a type of web application vulnerability that occurs when an attacker injects malicious SQL code into a web page or application. This can lead to unauthorized access to sensitive data, modification of data, or even complete system compromise. To prevent SQL injection, web application developers need to follow best practices such as parameterized queries and input validation. In this manual, we will cover the steps to manually test for SQL injection vulnerabilities.

Step 1: Identify the target

The first step is to identify the target web application that you want to test for SQL injection. You can use various tools like Nmap, Port Scanners, and Web Application Scanners to identify potential targets.

Step 2: Identify the input points

Once you have identified the target application, the next step is to identify the input points. Input points are the areas in the application where a user can enter data. Some examples of input points include search fields, login forms, and contact forms.

Step 3: Test for SQL injection

Now that you have identified the input points, you can begin testing for SQL injection. There are several methods you can use to test for SQL injection, including manual testing and automated tools.

Manual testing involves entering special characters and SQL queries into input fields to see if the application responds with an error message or displays unexpected behavior. For example, you can enter a single quote (') into a search field and see if the application returns an error message. If the application does not properly handle the single quote, it may be vulnerable to SQL injection.

Another manual testing technique is to use Boolean logic to infer information about the underlying database. For example, you can enter "OR 1=1" into a login form and see if the application grants access without requiring a valid username and password. If the application grants access, it may be vulnerable to SQL injection.

Automated tools like SQLMap can also be used to test for SQL injection. SQLMap automates the process of finding and exploiting SQL injection vulnerabilities in web applications.

Step 4: Exploit the vulnerability

If you have identified a SQL injection vulnerability, the next step is to exploit it. Exploiting a SQL injection vulnerability can give you access to sensitive data or even allow you to take control of the underlying system.

To exploit a SQL injection vulnerability, you can use SQL queries to extract data or modify the database. For example, you can use the UNION operator to combine the results of two SQL queries and retrieve data from the database.

It is important to note that exploiting a SQL injection vulnerability without permission is illegal and can result in severe consequences.

Step 5: Remediate the vulnerability

If you have identified a SQL injection vulnerability, it is important to remediate it as soon as possible. The best way to remediate a SQL injection vulnerability is to use parameterized queries or prepared statements to handle user input. Parameterized queries separate user input from SQL code, making it impossible for an attacker to inject malicious SQL code.

In addition to parameterized queries, input validation and sanitization can also help prevent SQL injection vulnerabilities. Input validation involves verifying that user input meets certain criteria, such as data type and length. Input sanitization involves removing or encoding special characters that could be used to inject SQL code.

In conclusion, manual SQL injection testing can be a time-consuming process, but it is an essential step in securing web applications. By following best practices and testing for SQL injection vulnerabilities, web application developers can protect their applications from malicious attacks.