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Security Best Practices in SQL Server: Fortifying Your Data Fortress

In our digital age, data is the lifeblood of businesses. Data loss, unauthorized access, manipulation, or leakage can be a fatal blow for the strongest. This is especially true for every system that stores and manages data.

The importance of database security cannot be overstated. Implementing best practices and ensuring reliable security are critical to protecting our data. So, as you can understand, today we will speak about data security in Microsoft SQL Server.

These are some essential best practices to take into consideration. Let's start with the easiest and continue to the hardest.

Harden the foundation

  • Keep your software updated. Apply Windows updates, cumulative updates, security patches, hotfixes, and improvements as often as possible. Most software makers, release updates addressing vulnerabilities and security flaws. The purpose of that is to safeguard your system. Microsoft, in most cases, is doing that even after the "End of Support" day.

  • Remove all unnecessary applications from the database servers. For example, Internet Browsers, Toolbars, WinZip, and even Notepad++, that very much loved by the developers.

  • Disable unnecessary services. For example, the SQL Server Browser can expose your server to vulnerabilities. Enable services essential to your specific needs only.

  • Disable Internet access on your servers.

  • Use anti-virus, anti-malware and firewall, even for database servers.

  • Use a network firewall to protect your network from unauthorized access.

Strong Authentication and Access Control

  • Strong password policy - Enforce complex passwords with regular rotation and change policies. BTW, for SQL Server on Linux, the password can be changed online by ssql.conf utility. This password change does not require any SQL Server restart.

  • Lead using a password manager to generate and manage strong credentials.

  • Avoid single user usage - each one must use his own user & password only.

  • Limit surface area: Use VPN and minimize the number of open ports. Allow connections from authorized IP addresses only. Restricting access helps prevent unauthorized attempts to breach your system.

  • Use Windows Authentication: Leverage Active Directory user accounts and group policies for enhanced security and centralized control.

  • Avoid using SQL Server authentication unless necessary.

  • The least privilege principle. Grant users only the smallest permissions required for their specific tasks. This reduces the potential damage if an account gets hacked.

  • Remove retired employees' permissions and users.

  • Remove Orphaned users.

  • Restrict RDP connections.

  • Lead the "lock the computer on your leaving" policy in the company.

Monitoring, auditing, and alerting

  • Log and monitor user activity. Track all database access and activity to detect suspicious behavior and potential breaches.

  • Set up and configure alerts to notify you of unusual activity. For example, failed login or unauthorized access attempts. Connections from outside allowed IPs range. Connections of service providers that stop working with your company.

  • Audit your logs. Conduct audits of security logs to identify potential vulnerabilities and fix them quickly.

Backup and Disaster Recovery

  • Create a robust backup strategy. Ensure that your databases are backed up to a secure location regularly. That can be hourly, daily, weekly, or even monthly, according to your workload and data changes.

  • Test your backups. Test your backups to ensure they are reliable and usable in case you need to restore your data. That can be performed once in some time or for each backup.

  • Create a disaster recovery plan. Create a detailed strategy for recovering your systems and data in the event of a disaster.

  • Consider inherent disaster recovery capabilities. For example, AlwaysOn, mirroring, log shipping, VM snapshot restore, or any custom solution.

Data Protection and Encryption

It is a very relevant subject, especially given the concern for the GDPR! Which is relevant to many other compliance regulations and data protection needs. Here we have some variations.

  • Protect your data at Rest:

  • Protect your data in Transit:

  • Backup Encryption. It allows you to encrypt database backups so that even if the backup file is stolen or lost, the data within it remains protected. Backup encryption uses a certificate or asymmetric key to encrypt the backup.

  • Consider Dynamic Data Masking. Hides sensitive data from unauthorized viewers and users. It's like covering confidential information with something. Not all users in a company should have access to data, even if they have a fixed db_datareader database role.

  • Use "Row-level security" for multi-tenancy. All tenant's data can be stored in the same DB, but must be prevented from the cross-tenant access.

  • Store your encryption keys in safe place.


Even the best defenses can be breached. That's why we need a complex defense and a "plan B", aka a way to recover if things go wrong.

Security is not a one-time fix; it's an ongoing journey. By following best practices, we can build a robust defense for our SQL Server. Ensuring our data remains safe and secure.

Be proactive and vigilant, and strive to improve your defenses. After all, in the digital world, a strong data fortress is key to our success!


Additional & Recommended reading:




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