How to Make Your SQL Server More Secure

This article explains how to make your SQL server more secure and how DbVisualizer can help you to achieve the goal.

Tools used in this tutorial

DbVisualizer, top rated database management tool and SQL client
The Microsoft SQL Server Database

SQL Server is a widely-used relational database management system that is essential to the operation of many businesses and organizations. As such, securing SQL Server databases is critical to safeguard sensitive information and ensure data integrity. SQL Server databases often store sensitive information, including financial data, business information, and personal details. A breach of the database can lead to the leakage of sensitive information and financial damages to organizations. Furthermore, unauthorized access to your database can allow for data manipulation and corruption, which can have severe business and personal consequences. This article discusses how we can prevent these by making our SQL Server infrastructure more secure

Frequent Database Threats

Understanding common database threats means that you can prepare for the most probable risks. Before diving into security enhancing strategies, let’s find out the top three database threats.

SQL injection is a top threat in which an attacker injects malicious code into a database's SQL statement, allowing them to access or manipulate sensitive data. This can happen when input fields on a web page, such as a login form, are not properly validated or sanitized. This can allow an attacker to alter the intended SQL query and gain unauthorized access to the database. To prevent this, it's important to validate user input, use prepared statements or stored procedures, and limit user privileges to prevent unauthorized access to the database.
Data leakage occurs when sensitive information is accidentally or intentionally leaked to unauthorized entities. This can happen through various ways, like data breaches, weak access controls, misconfigured cloud services, or even through employees sharing sensitive information. To avoid data leakage, we can consider to implement strong access controls and encrypt sensitive information before sending it over networks. Plus, regular database audits and security assessments can help identify and address potential data leakage risks before they are exploited by attackers.
Privilege escalation is when an attacker can gain elevated access to a database by exploiting vulnerabilities in the system. This can happen when user accounts have too many permissions or when poor password policies are in place. This can allow an attacker to get access to critical data or take actions that need to be restricted. Managing user privileges properly and tightening access to the minimum resources are good practices to prevent privilege escalation. In addition, software upgrades and security patches can block unauthorized or unintended escalation. Although the types of the threats are different, they share common preventive measures such as encryption, access control, and auditing. The next section describes them more in detail.

Making SQL Server More Secure

Enhancing SQL Server security requires various methods, including using strong passwords, limiting access to the server and specific databases, implementing role-based access control, and regularly patching the server software. These multi-pronged strategies help to ensure that the server is protected from both internal and external threats. The methods are applicable not only to SQL server but also to all DBMS, so understanding these strategies can help you to build strong security fundamentals. Let’s focus on five main areas.

File and Data encryption

In SQL Server, you can use the built-in encryption features to encrypt your files for additional security. The main encryption feature in SQL Server is TDE or Transparent Data Encryption. TDE encrypts the entire database files, including the log files. To encrypt a database with TDE, you need to first create a master key and a certificate and then enable TDE on the database. Another method is cell-level encryption, which allows you to encrypt specific columns in a table. This method can be useful if you only want to encrypt sensitive data in specific columns rather than the entire database. To encrypt a column using cell-level encryption, you need to create a symmetric key and use it to encrypt the column.

Column-level Protection

You can implement column-level protection to restrict access to specific columns in a table based on user roles and permissions. To implement column-level protection in SQL Server, you can use the Dynamic Data Masking (DDM) feature, which allows you to mask specific columns in a table by replacing sensitive data with a mask like asterisks or a default value. This feature can be configured at the database level, and it is transparent to the application, meaning that the application does not need to be modified to use DDM.

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Row-level protection

You can also utilize Row-level Security (RLS) in SQL Server. RLS allows you to define security predicates, which are conditions that determine which rows a user is allowed to access. These predicates can be based on the user's role or other attributes. Once the predicates are defined, they can be assigned to the roles or users. RLS can be used with SELECT, UPDATE, DELETE and INSERT statements. To implement RLS, you will first need to create a security predicate function that defines the conditions for accessing the data. Next, you will create a security policy that references the predicate function and assigns it to the table or view that you want to protect.

User Security

SQL Server Authentication allows you to create and manage user accounts within the SQL Server itself. By using SQL Server Authentication, you can create custom roles and assign specific permissions to those roles. It is recommended to use strong and complex passwords for the SQL Server logins and to use the password policy feature to enforce the password policies.

SQL Server provides the ability to create and manage database-level roles, which allow you to assign specific permissions to users at the database level. This allows you to create a custom security model that is specific to your company needs. In addition, you can also use the built-in roles, like db_owner, db_datareader, and db_datawriter, to grant specific permissions to the users. It is important to use the principle of least privilege, which means that the users should only have the permissions they need to perform their job.

Auditing

Auditing is a practice to track and record various events within the database, such as user logins, changes to data, and other sensitive actions. This information can be used to detect and investigate security breaches and to improve the overall security of your SQL Server environment. You can use SQL Server Audit to create and configure audits to track various events and actions. You can specify the type of types to track and the location of audit logs. If you’re using the auditing feature, it is important to review the audit logs regularly. It is recommended to store audit logs in a secure location and to protect it from unauthorized access.

Enhancing security using DbVisualizer

We have learned five strategies to make your SQL Sserver more secure. However, the fact is when we put too much focus on security, not only efficiency but also convenience can be decreased. DbVisualizer provides a balanced way that meets both ends. In this section, we will learn how we can use its authentication feature for secure access to your database.

DbVisualizer SSH Connection Authentication.<br> — DbVisualizer SSH Connection Authentication.

On the left pane, select your database.
On the right pane, select the Properties tab.
Under your database name, click Authentication.
Check Require UserId or/and Require Password that suits your needs.
Click Apply.

Click the General tab.
Expand Database Connection and select SSH Settings.
Under SSH Authentication, check Require UserId or/and Require Password/Passphrase.
Click Apply.

These identification features can ensure a secure connection to your database and prevent unauthorized access.

Conclusion

In this article, we learned how to make your SQL server more secure. Database security is crucial for protecting sensitive information and ensuring the integrity of business operations. SQL injection, data leakage, and privilege escalation are just a few threats that can compromise a database. To protect against these threats, organizations should embrace security in various areas of their database. DbVisualizer can help you to achieve your security goals with strong security features. Find out more features of DbVisualizer.

About the author

Igor Bobriakov is an entrepreneur and educator with a background in marketing and data science. His passion is to help small businesses and startups to utilize modern technology for growth and success. Igor is Data Scientist and ML Engineer. He founded Data Science School in 2016 and wrote numerous award-winning articles covering advanced tech and marketing topics. You can connect with him on LinkedIn or Twitter.