Open Source and Security: Why Openness Is the Best Defense

The Cliché

Open source is often equated with “open” and thus mistakenly with “insecure.” Many believe that publicly accessible code means that anyone can access systems or sensitive data. But that is a misconception.

In this context, openness means transparency, not permissiveness.

The source code of software is publicly available so that it can be reviewed and improved but that does not mean that everyone automatically has access to productive systems or company data.

This transparency builds trust because errors are visible, traceable, and verifiable. Projects such as Linux, Kubernetes, and PostgreSQL have proven for years that open software is secure, stable, and reliable and forms the basis of many security-critical systems. 

Technical Consideration of Safety

The so-called “many eyes principle” is one of the biggest security advantages of open source: the more people check the code, the faster vulnerabilities are detected.

While proprietary systems usually only have a limited internal team performing security checks, open source systems undergo a permanent, global peer review process. Every code change is checked, and automated security tests (e.g., using tools such as SonarQube, Trivy, or GitHub Advanced Security) continuously scan the code for vulnerabilities.

In addition, technical mechanisms ensure security:

• Signed commits and releases prevent manipulated code changes from being imported unnoticed.
• Reproducible builds ensure that the published code corresponds exactly to the tested source code.
• Cryptographic hash checks ensure the integrity of packets and containers.

This creates a security model that is not based on blind trust in a manufacturer, but on verifiable quality. Openness here means that everyone can understand why a piece of software is secure.

Open Source vs. closed Software

While open source focuses on transparency and traceability, proprietary software is often based on the principle of “security through obscurity” i.e., security through secrecy.

This sounds reasonable at first, but it has disadvantages: if a vulnerability is discovered, users are completely dependent on the manufacturer to decide if and when it will be fixed.

In open source systems, every company can verify for itself how secure a piece of software is and respond immediately if necessary.

Closed software requires trust in statements that cannot be verified.

In short: Proprietary software demands trust—open source earns it.

The Security Mechanisms

Modern open source projects are organized in a highly professional manner and rely on strict security standards. These include:

• Security gates in CI/CD pipelines that block insecure code before it is released.
• Verified contributor identities to prevent supply chain attacks.
• Regular penetration tests and independent audits.
• Coordinated security response teams that prioritize reported vulnerabilities and fix them promptly.

Many projects, such as Debian or Kubernetes, operate their own security advisory boards that define processes and monitor standards.

This structured openness ensures that vulnerabilities are not covered up but remedied quickly, documented, and traceable.

Can Open Source be “shielded”?

A common misconception is: “If something is open source, anyone can access it.”

That's not true. Openness refers exclusively to the source code, not to a company's data or instances.

Companies can run open source software entirely in protected environments, on their own servers or in a private cloud. Only authorized persons have access. 

A good example of this is the open source ERP system Odoo. Although Odoo's source code is publicly available, the instance operated by a company runs exclusively internally. No one outside the company can view accounting data, customer data, or internal processes, and that is not the purpose of open source.

On the contrary: companies can adapt, extend, or harden the source code to perfectly suit their own requirements. These changes remain private and are subject to the company's own security guidelines. The public code is the basis, the operational implementation is and remains protected.

Open source thus combines two advantages: transparent technology and full control over your own operations.

Our Recommendations for Action

The openness of open source is a strength, but it requires experience and structure.

Companies should establish clear security processes to make the most of the benefits:

• Regular Patch Management: Security updates must be installed promptly.
• Dependency Monitoring: Special tools help to automatically check libraries.
• Zero Trust strategy: Every component is verified independently - whether open source or proprietary.
• Continuous Monitoring: Runtime monitoring with tools such as Falco detects suspicious activity in real time.

These measures ensure that open source systems are not only secure, but also remain secure.

However, many security incidents are not caused by open source itself, but by incorrect implementation.

Often, outdated versions are used for too long, external libraries are integrated without critical review, or responsibilities are not clearly defined.

To avoid this, you need expertise and structured processes. This is where OPaaS comes in:

With our many years of expertise in the integration, hardening, and maintenance of open-source systems, we ensure that software not only works, but remains secure in the long term.

We support companies from the selection of suitable components and the security concept to maintenance and monitoring. Our experts know what matters in modern IT architectures and how to use open source in such a way that it integrates perfectly into existing security structures.

When you work with experienced partners, you don't have to worry about maintenance and support and can concentrate on what really matters: the success of your own company.