Why open source is just as secure as closed source

Security is one of the most discussed topics in IT. Especially when it comes to strategic systems, the same question keeps coming up: Is closed source software more secure than open source?

The short answer: No.

Open source is not inherently less secure than closed source. When used correctly, open source is at least as secure, and often even more transparent and easier to control.

This blog article classifies common security assumptions and shows why open source and security are not a contradiction.

A common misconception: secrecy = security

A common understanding of security is:

‘If no one sees the code, no one can attack it.’

This principle is known as security through obscurity. At first glance, it seems logical, but in practice it is problematic:

Attackers analyse software not via the source code, but via runtime, network behaviour and interfaces
Security gaps often arise from misconfigurations or design errors
With closed source, users have to trust the manufacturer without being able to check for themselves.

Pure secrecy does not protect against attacks. It merely reduces transparency for operators and customers.

Open source: transparency as a security factor

Open source software takes a different approach: the code is openly accessible (not to be confused with user data), verifiable and auditable.
What is often perceived as a risk is actually a strength.

Advantages of openness

• Many eyes see more
  Security vulnerabilities are discovered more quickly because developers, security experts and organisations can analyse the code.
• Traceability
  It is visible what a software really does: no hidden functions, no silent data leaks, no backdoors.
• Independent audits
  Security checks are possible without being dependent on the manufacturer or marketing statements.
• Faster responsiveness
  Critical fixes can be developed and rolled out promptly, even independently of the original provider.

Transparency creates control, and control is a basic prerequisite for security.

You can find more advantages of open-source software in our blog article What is open-source software and what are its advantages?

Security is a process, not a licensing model

One key point is often overlooked:

‘It is not open or closed source that makes a system secure, but how it is operated.’

Security depends on:

• clean IT architecture
• consistent patch management
• regular audits and pentests
• minimal permissions
• clear backup and recovery concepts
• monitoring and logging
• user security awareness

A poorly operated open source system is insecure.
The same applies to a poorly maintained closed source system.

However, open source offers one advantage: risks and dependencies are visible and can be actively managed.

Digital sovereignty as part of security

Security is not only technical, but also strategic.

Open source enables:

• Independence from individual manufacturers
• Avoidance of lock-in
• Full control over data, operation and further development
• Long-term capacity to act

This sovereignty is an essential component of modern IT security.

Conclusion

Open source is no less secure than closed source.
Through transparency, verifiability and control, open source provides a robust foundation for secure and future-proof IT solutions.

Security does not come from secrecy, but from openness (including source code), responsibility and clean operation.

Open source means:

• No black boxes
• No blind dependencies
• No security promises without proof

Instead, it means digital sovereignty through traceable, secure technology.