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For resilient applications, security should never be an afterthought. Embed it from the start. Security design principles provide a blueprint for creating systems that resist threats by default rather than relying on ad-hoc fixes.
Integrating these security principles early in development can reduce vulnerabilities, simplify compliance, and minimize costly security incidents. Here’s a guide to best practices and how to implement them.
Importance of Security Design Principles
Effective security starts with design, not just reaction. By integrating fundamental security design principles into the development process, you create systems that can withstand attacks, protect data integrity, and maintain availability. This preventative approach makes it more difficult for attackers to exploit vulnerabilities, reducing the risk of breaches and business disruptions.
The security by design principle is reflected in the Open Worldwide Application Security Project (OWASP) Top 10, which lists the most significant digital risks. A04:2021 – Insecure Design ranks as the fourth most impactful application security risk, showing just how important this factor is in creating strong applications.
10 Security Design Principles
Security design principles create a structured framework for minimizing risk and withstanding modern threats. These cybersecurity design principles, based on OWASP’s Principles of Security Engineering, play a significant role in software security design, helping you implement effective defenses early in development.
1. Least Privilege
Restrict user and process permissions to only what is necessary—a practice also known as the principle of least privilege (POLP). It minimizes the impact of security breaches because if attackers do get through, they can only access some systems.
POLP is important for clients and employees as well as non-human identities like software processes and automated scripts. It can apply to everything from user permissions to API integrations, limiting access at every level reduces the attack surface. One common implementation is role-based access control (RBAC), where users receive only the permissions required for their specific job function.
2. Separation of Duties
Spreading key responsibilities across multiple users or systems prevents a single point of failure. This means no single person has unchecked control over sensitive actions, reducing insider threats and accidental misconfigurations.
For example, developers shouldn’t be responsible for writing and approving code changes in software deployment. Instead, peer code reviews, automated security checks, and approval workflows ensure accountability. This principle is especially pertinent in financial systems, where requiring multiple approvals for high-value transactions can prevent fraud. DevOps security best practices further emphasize this layered approach to accountability.
3. Open Design
Security should rely on well-tested, transparent protections. The open design principle means that attackers shouldn’t be able to break a system simply by understanding how it works. Instead, developers should use publicly reviewed encryption standards, well-documented authentication mechanisms, and industry-proven security models to avoid leaving gaps.
This principle is especially important in cryptographic systems. Relying on proprietary encryption methods instead of standardized ones like Advanced Encryption Standard (AES) or Rivest–Shamir–Adleman (RSA) can introduce weaknesses. Secure software should assume attackers can inspect the code, and the code still remains secure.
4. Defense in Depth
No single security measure can fully protect an application. A defense-in-depth strategy layers multiple security controls to create redundancies, making it harder for attackers to succeed. This layered security approach is necessary in DevSecOps environments, where security is built into the SDLC instead of applied as an afterthought.
A well-architected security model includes firewalls, endpoint protection, and network segmentation. Additionally, logging and monitoring tools help teams detect suspicious activity early. For example, if an attacker bypasses an application’s authentication system, a second layer—like anomaly detection on login behavior—can still flag and mitigate the threat.
5. Fail Securely
When a system encounters an error, it should default to a secure state instead of exposing sensitive data or granting unintended access. Misconfigured error handling can create severe vulnerabilities—for example, improperly handling authentication failures could allow brute-force attacks.
A secure system should enforce session timeouts, reject unexpected inputs, and avoid providing error messages that disclose internal application details. If an application crashes, it shouldn’t expose database contents or stack traces to users.
6. Economy of Mechanism
Overly complex systems introduce unnecessary risk, making them harder to audit and maintain. Simplifying security controls reduces the likelihood of vulnerabilities and misconfigurations.
A secure system should use clear, concise code with well-documented security measures. Unnecessary complexity often leads to security gaps like excessive permissions, convoluted authentication mechanisms, or redundant access control rules.
7. Complete Mediation
Instead of assuming that permissions remain valid indefinitely, enforce access controls whenever a request occurs. A classic example of a failure in mediation is session hijacking, where an attacker takes over a logged-in session without re-authentication.
To prevent this, systems should revalidate permissions frequently and log out inactive sessions. Continuous authorization verification maintains strong identity security, ensuring only authorized users can access vital resources.
8. Secure Defaults
Enabling security features by default prevents misconfigurations that could lead to breaches. Design applications with automatic security features. You can’t rely on the user to enable encryption manually or configure strict access controls themselves.
Common secure defaults include requiring multi-factor authentication, encrypting sensitive data automatically, and restricting API access. These practices align with secure SDLC guidelines, reducing human error while improving security compliance.
9. Psychological Acceptability
Security measures should be user-friendly. Otherwise, users might not make the effort to comply. They may store passwords insecurely or use weak credentials if authentication requirements are too complex.
A well-balanced, user-friendly security model offers convenience while maintaining strong protection. Single sign-on (SSO), biometric authentication, and adaptive access controls all make security seamless without compromising protection.
10. Minimization of Attack Surface
When adopting application security best practices, incorporate attack surface reduction into your workflows to maintain a strong security posture. Reducing unnecessary services and APIs limits potential entry points for malicious actors.
Attack surface reduction includes disabling unused ports, minimizing software dependencies, and enforcing strict input validation. Regular security audits also help identify and remove redundant components, improving overall protection.
Reinforce Security Design Principles With Legit Security
Implementing security design principles strengthens application security, reduces vulnerabilities, and helps systems withstand evolving threats. But securing applications at scale requires visibility and continuous monitoring. That’s where Legit Security comes in.
The Legit Security ASPM platform provides real-time security insights, automated policy enforcement, and security integration across the SDLC. With Legit Security, you can proactively safeguard your applications, streamline compliance, and maintain a security-by-design approach—all without slowing development.
Book a demo today to see the difference.