You're upgrading legacy systems with modern features. How can you ensure security is not compromised?

The best practice in this situation is to implement automated testing for the modified system, including UI, functional, contract, unit, performance, and integration tests. These tests should be integrated into the CI/CD pipeline to ensure that changes don't negatively impact the system's functionality or performance. However, adding unit tests to a legacy codebase is often difficult, expensive, or time-consuming. In such cases, it’s more practical to cover the functionality with tests that are less dependent on the internal system code, such as UI tests or API tests using external tools like Postman or Selenium. Monitoring code coverage is essential to ensure that all critical parts of the legacy system are adequately tested.

The first thing is a complete security audit of the legacy systems, that means outdated software, insecure configurations, and look up all the issues and comments made by the teams involved with the systems. Next, we should apply all the patches and updates that can quickly be applied, this may resolve a lot of issues covered by the new system, that may buy the team time to deliver the new solutions. Make sure to properly isolate the legacy system within the network as you gradually introduce the new system, reducing vulnerable surfaces. Running a complete suite of pen-tests & updating the firewalls and API gateways at each step. not forgetting the IAM roles! Of course, monitoring and logging will be paramount during this time.

When upgrading legacy systems, prioritize security by conducting thorough vulnerability assessments, implementing modern encryption standards, and using secure coding practices. Regularly audit and test the system to ensure new features don’t introduce security risks. This approach keeps both performance and protection in balance.

Upgrading legacy systems requires prioritizing security. Assess vulnerabilities and document existing measures. Implement robust change management and gradually introduce modern features, testing each for security flaws. Use automated testing tools and conduct regular penetration tests. Keep components updated with latest security patches. Implement strong authentication and data encryption. Follow the principle of least privilege. Train your team on new security best practices and establish a clear incident response plan. Remember, security is an ongoing process, not a one-time fix.