#sqlserver

This Patch Tuesday release fixes critical Windows, Office, Azure, and Xbox vulnerabilities, including two zero-days in SMB Server and SQL Server that could allow privilege escalation and denial-of-service exploits.

Source: BleepingComputer | BleepingComputer

Last year in college , I had the opportunity to dive deep into SQL. The course was made even more exciting by an amazing instructor . Fast forward to today, and I regularly use SQL in my backend development work with PHP. Today, I felt the need to refresh my SQL knowledge a bit, and that's why I've put together three posts aimed at helping beginners grasp the fundamentals of SQL.

Understanding Relational Databases

Let's Begin with the Basics: What Is a Database?

Simply put, a database is like a digital warehouse where you store large amounts of data. When you work on projects that involve data, you need a place to keep that data organized and accessible, and that's where databases come into play.

Exploring Different Types of Databases

When it comes to databases, there are two primary types to consider: relational and non-relational.

Relational Databases: Structured Like Tables

Think of a relational database as a collection of neatly organized tables, somewhat like rows and columns in an Excel spreadsheet. Each table represents a specific type of information, and these tables are interconnected through shared attributes. It's similar to a well-organized library catalog where you can find books by author, title, or genre.

Key Points:

Tables with rows and columns.

Data is neatly structured, much like a library catalog.

You use a structured query language (SQL) to interact with it.

Ideal for handling structured data with complex relationships.

Non-Relational Databases: Flexibility in Containers

Now, imagine a non-relational database as a collection of flexible containers, more like bins or boxes. Each container holds data, but they don't have to adhere to a fixed format. It's like managing a diverse collection of items in various boxes without strict rules. This flexibility is incredibly useful when dealing with unstructured or rapidly changing data, like social media posts or sensor readings.

Key Points:

Data can be stored in diverse formats.

There's no rigid structure; adaptability is the name of the game.

Non-relational databases (often called NoSQL databases) are commonly used.

Ideal for handling unstructured or dynamic data.

Now, Let's Dive into SQL:

SQL is a :

Data Definition language ( what todays post is all about )

Data Manipulation language

Data Query language

Task: Building and Interacting with a Bookstore Database

Setting Up the Database

Our first step in creating a bookstore database is to establish it. You can achieve this with a straightforward SQL command:

CREATE DATABASE bookstoreDB;

SQL Data Definition

As the name suggests, this step is all about defining your tables. By the end of this phase, your database and the tables within it are created and ready for action.

1 - Introducing the 'Books' Table

A bookstore is all about its collection of books, so our 'bookstoreDB' needs a place to store them. We'll call this place the 'books' table. Here's how you create it:

CREATE TABLE books ( -- Don't worry, we'll fill this in soon! );

Now, each book has its own set of unique details, including titles, authors, genres, publication years, and prices. These details will become the columns in our 'books' table, ensuring that every book can be fully described.

Now that we have the plan, let's create our 'books' table with all these attributes:

CREATE TABLE books ( title VARCHAR(40), author VARCHAR(40), genre VARCHAR(40), publishedYear DATE, price INT(10) );

With this structure in place, our bookstore database is ready to house a world of books.

2 - Making Changes to the Table

Sometimes, you might need to modify a table you've created in your database. Whether it's correcting an error during table creation, renaming the table, or adding/removing columns, these changes are made using the 'ALTER TABLE' command.

For instance, if you want to rename your 'books' table:

ALTER TABLE books RENAME TO books_table;

If you want to add a new column:

ALTER TABLE books ADD COLUMN description VARCHAR(100);

Or, if you need to delete a column:

ALTER TABLE books DROP COLUMN title;

3 - Dropping the Table

Finally, if you ever want to remove a table you've created in your database, you can do so using the 'DROP TABLE' command:

DROP TABLE books;

To keep this post concise, our next post will delve into the second step, which involves data manipulation. Once our bookstore database is up and running with its tables, we'll explore how to modify and enrich it with new information and data. Stay tuned ...

Understanding and Preventing SQL Injection (SQLi) in Symfony Applications

SQL Injection (SQLi) remains one of the most common and damaging vulnerabilities affecting web applications. This guide will dive into what SQLi is, why Symfony developers should be aware of it, and practical, example-based strategies to prevent it in Symfony applications.

What is SQL Injection (SQLi)?

SQL Injection occurs when attackers can insert malicious SQL code into a query, allowing them to access, alter, or delete database data. For Symfony apps, this can happen if inputs are not properly handled. Consider the following unsafe SQL query:

php

$query = "SELECT * FROM users WHERE username = '" . $_POST['username'] . "' AND password = '" . $_POST['password'] . "'";

Here, attackers could input SQL code as the username or password, potentially gaining unauthorized access.

How to Prevent SQL Injection in Symfony

Symfony provides tools that, when used correctly, can prevent SQL Injection vulnerabilities. Here are the best practices, with examples, to secure your Symfony app.

1. Use Prepared Statements (Example Included)

Prepared statements ensure SQL queries are safely constructed by separating SQL code from user inputs. Here’s an example using Symfony's Doctrine ORM:

php

// Safe SQL query using Doctrine $repository = $this->getDoctrine()->getRepository(User::class); $user = $repository->findOneBy([ 'username' => $_POST['username'], 'password' => $_POST['password'] ]);

Doctrine’s findOneBy() automatically prepares statements, preventing SQL Injection.

2. Validate and Sanitize Input Data

Input validation restricts the type and length of data users can input. Symfony’s Validator component makes this easy:

php

use Symfony\Component\Validator\Validation; use Symfony\Component\Validator\Constraints as Assert; $validator = Validation::createValidator(); $input = $_POST['username']; $violations = $validator->validate($input, [ new Assert\Length(['max' => 20]), new Assert\Regex(['pattern' => '/^[a-zA-Z0-9_]+$/']) ]); if (count($violations) > 0) { // Handle invalid input }

In this example, only alphanumeric characters are allowed, and the input length is limited to 20 characters, reducing SQL Injection risks.

3. Use Doctrine’s Query Builder for Safe Queries

The Symfony Query Builder simplifies creating dynamic queries while automatically escaping input data. Here’s an example:

php

$qb = $this->createQueryBuilder('u'); $qb->select('u') ->from('users', 'u') ->where('u.username = :username') ->setParameter('username', $_POST['username']); $query = $qb->getQuery(); $result = $query->getResult();

By using setParameter(), Symfony binds the input parameter safely, blocking potential injection attacks.

Using Free Tools for Vulnerability Assessment

To check your application’s security, visit our Free Tools page. Here’s a snapshot of the free tools page where you can scan your website for SQL Injection vulnerabilities:

These tools help you identify security issues and provide guidance on securing your Symfony application.

Example: Vulnerability Assessment Report

Once you’ve completed a vulnerability scan, you’ll receive a detailed report outlining detected issues and recommended fixes. Here’s an example screenshot of a vulnerability assessment report generated by our free tool:

This report gives insights into potential SQL Injection vulnerabilities and steps to improve your app’s security.

Additional Resources

For more guidance on web security and SQL Injection prevention, check out our other resources:

Pentest Testing – Get expert penetration testing services.

Cyber Rely – Access comprehensive cybersecurity resources.

Conclusion