In our digitally dominated world, every click, every search, and every login is a silent conversation between user interfaces and the vast, often invisible databases that power the internet. From the moment you enter your credentials on a login page to the instant you hit the search button on your favorite online store, your interactions are translated into SQL queries that travel back and forth, fetching or storing data on your behalf. While crucial for modern web experiences, this seamless interaction can also be its weakest link due to SQL injection (SQLi). This vulnerability emerges when user inputs are not properly sanitized, allowing attackers to inject malicious SQL commands. These commands can lead to unauthorized data access, data integrity corruption, or total database control.
What is SQL
Injection?
SQL
injection, often known as SQLi, is the most common and frequently used
web-based attack, where hackers inject malicious SQL statements (like SELECT *
FROM users WHERE username = ' ' OR '1'='1' AND password = ' ') into the application's
database to modify an SQL-based database and access potentially valuable
information. These statements manage a database server that runs behind a web
application. It is a web security vulnerability susceptible to any web
application or website that uses SQL databases, such as Oracle, SQL Server, or
MySQL. It enables hackers to access sensitive or Personally Identifiable
Information (PII), alter, update, or delete database data, gain administrative
rights, and potentially control the application.
Types of SQL Injection
Attack
SQL injection attacks are categorized into three main types:
1. In-band SQL Injection (Classic)
In-band SQL injection is the most widely used and easily exploitable SQL injection attack.
There are two main categories of in-band SQL injection:
- Error-based SQLi: In this attack, the hacker carries out specific actions that trigger the database to produce error messages to gain information about the database's structure.
- Union-based SQLi: In this attack, the hacker uses the UNION SQL operator to merge multiple select statements into a single HTTP response to retrieve the desired data.
2. Inferential SQL Injection (Blind)
An inferential SQL injection attack emerges when a web application is vulnerable to SQL injection. They depend on the server's response and behavior patterns, which makes them slower to run but potentially just as harmful.
There are two main categories of inferential SQL injection:
- Boolean-based SQLi: In this attack, the hacker sends a query to the database, requesting the application to produce an outcome. The outcome will alter depending on whether the query is true or false.
- Time-based SQLi: In this attack, the hacker sends a query to the database, causing the database to wait for a short period before responding with true or false information.
3. Out-of-band SQL Injection (OOB SQLi)
OOB SQLi is not commonly used. Hackers use it only when certain features are enabled on the database servers used by web applications. The primary purpose of this attack is to replace in-band and inferential SQLi approaches.
Impacts of SQL Injection Attack
● Disclose confidential and sensitive
information
● Compromise the accuracy of data
● Provide an attacker with entire system
access
● Compromise the privacy of users
● Provides a system administration control
to the hacker
You
can also refer: How Does an SQL Injection Attack Work?
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