SQL injection is a type of web attack that allows attackers to inject malicious SQL code into an application’s database queries. This can be done by exploiting vulnerabilities in the application’s input validation process. Once the attacker’s code is executed, they can gain unauthorized access to sensitive data, modify or delete data, or even take control of the database server.
How SQL injection works:
SQL injection attacks typically work in one of two ways:
In-band SQL injection: The attacker injects malicious SQL code into a form field or other input field that is processed by the application. The application then executes the code without properly validating it, which allows the attacker to gain access to the database.
Out-of-band SQL injection: The attacker injects malicious SQL code into a form field or other input field that is processed by the application. The application then executes the code and returns the results to the attacker through a different channel, such as an email address or a web page.
Impact of SQL injection attacks:
SQL injection attacks can have a devastating impact on web applications. Attackers can use SQL injection to:
Steal sensitive data, such as usernames, passwords, credit card numbers, and social security numbers.
Modify or delete data, which can cause disruptions to the application’s functionality.
Take control of the database server, which can give the attacker complete access to all of the data in the database.
Protecting against SQL injection attacks:
There are a number of things that web developers can do to protect their applications from SQL injection attacks, including:
Validate all user input: Before executing any database queries, the application should validate all user input to ensure that it is safe. This can be done using a variety of techniques, such as regular expressions and whitelists.
Use parameterized queries: Parameterized queries allow developers to separate the SQL code from the user input. This helps to prevent attackers from injecting malicious code into the SQL queries.
Keep software up to date: Software vendors regularly release security patches to fix known vulnerabilities. Web developers should make sure to install all security patches as soon as they are available.
Note:
If you are a web developer, please make sure that you are taking the necessary precautions to protect your applications from SQL injection attacks. This includes validating all user input, using parameterized queries, and keeping your software up to date.
References:
https://pwning.owasp-juice.shop/companion-guide/latest/part2/injection.html
https://owasp.org/www-community/Injection_Flaws
https://owasp.org/www-community/attacks/Blind_SQL_Injection
https://wiki.owasp.org/index.php/Testing_for_NoSQL_injection
https://www.us-cert.gov/ncas/tips/ST04-015
https://portswigger.net/kb/issues/00101080_server-side-template-injection