What Is Security by Design?
Security by design embeds security measures at the core of product development, from initial concept to final deployment. This approach prioritizes identifying and mitigating security threats throughout the entire lifecycle of a product or system.
By integrating security principles early on, developers can address potential vulnerabilities before they become exploitation targets. This contrasts with traditional methods where security is often an afterthought, leading to costly retrofitting.
The security by design methodology is crucial for protecting data and systems against increasingly sophisticated cyber threats. It ensures that security mechanisms are foundational components of any system. Adopting this approach minimizes risk, fosters compliance with regulatory mandates, and builds resilience into the system architecture.
Security by Design Principles
Security by design is guided by principles that ensure systems are built with security at their core. These principles provide a framework for making design decisions that reduce risk, prevent common vulnerabilities, and support long-term resilience.
- Least privilege: Limit access rights for users, processes, and systems to only what is necessary. This minimizes potential damage from accidents or malicious activity by containing the scope of access.
- Defense in depth: Layer multiple security controls throughout the system to provide redundancy. If one layer fails, others remain in place to protect the system.
- Secure defaults: Ensure systems are secure out of the box, with restrictive default settings. Security features should be enabled by default, requiring deliberate action to weaken protections.
- Fail securely: Design systems to handle failures in a secure manner. When errors occur, they should not expose sensitive data or leave the system vulnerable to attack.
- Keep it simple: Avoid unnecessary complexity in system design, as it often introduces hard-to-detect vulnerabilities. Simple designs are easier to audit, test, and secure.
- Secure the supply chain: Evaluate and secure third-party components, including libraries, frameworks, and hardware. Vulnerabilities in external dependencies can compromise the entire system.
- Continuous validation: Implement ongoing testing and security assessments throughout the development lifecycle. Techniques like static analysis, dynamic testing, and penetration testing help uncover vulnerabilities early.
- Secure by default configuration management: Provide and enforce secure configurations through automated tools and policies. Systems should remain secure even as they scale or change over time.
Security by Design in Common Compliance Frameworks
Health Insurance Portability and Accountability Act (HIPAA)
HIPAA does not explicitly use the term “security by design,” but its security rule requires covered entities and business associates to implement administrative, physical, and technical safeguards that support the intent of the approach. For example, the rule emphasizes risk analysis and risk management (45 CFR §164.308(a)(1)), requiring organizations to identify potential risks and vulnerabilities to electronic protected health information (ePHI) and implement measures to reduce those risks.
Technical safeguards such as access controls, audit controls, integrity controls, and transmission security (45 CFR §164.312) also reflect core security by design principles. While HIPAA is flexible and technology-neutral, compliance demands that security considerations be integrated into system design and operations, particularly when handling or transmitting ePHI.
Payment Card Industry Data Security Standard (PCI DSS)
PCI DSS incorporates security by design concepts, especially in requirements related to secure system development and maintenance. Requirement 6 mandates the development of secure systems and applications, including secure coding practices, vulnerability management, and change control processes. Developers must follow industry standards for secure development, such as OWASP, and test applications for security flaws throughout their lifecycle.
Requirement 2 (secure configurations) and requirement 10 (logging and monitoring) also support security by design by ensuring systems are securely configured and continuously monitored for suspicious activity. The standard further emphasizes minimizing attack surfaces and limiting access based on business need to know, aligning closely with principles like least privilege and defense in depth.
NIST Cybersecurity Framework
The NIST cybersecurity framework (CSF) adopts a risk-based approach to managing cybersecurity, aligning well with security by design principles. Although it does not prescribe specific technical controls, it provides a structure (Identify, Protect, Detect, Respond, Recover) that encourages early and continuous consideration of security in system design.
Within the “Protect” function, the framework highlights secure software development processes (PR.IP-3), configuration management (PR.IP-1), and access control (PR.AC), all of which are central to security by design. NIST also offers more detailed guidance through publications like NIST SP 800-160, which focuses explicitly on engineering trustworthy secure systems.
Security by Design Implementation Strategies
Organizations should implement these measures to ensure security by design.
1. Define Security Objectives and Risk Tolerance
Begin by identifying critical assets—data, services, infrastructure—and assessing the impact of their compromise. Categorize these assets based on confidentiality, integrity, and availability requirements. Use this classification to define security goals, such as preventing unauthorized access, ensuring data accuracy, and maintaining uptime.
Next, perform a risk assessment to map threats to assets. Consider threat actors, attack vectors, likelihood, and potential impact. This helps establish acceptable risk levels, which guide the design of controls and investments. Document these tolerances and revisit them periodically.
2. Integrate Security into Development Processes
Security integration should start with requirement gathering. Include non-functional security requirements alongside performance and availability metrics. During design, apply architectural threat modeling using frameworks like STRIDE or PASTA to identify and mitigate attack surfaces.
In development, enforce secure coding standards such as those from OWASP or CERT. Embed linting tools, dependency checkers, and SAST into the build pipeline to catch issues early. Include security in code reviews and use infrastructure as code (IaC) scanning to identify misconfigurations.
Security gates in CI/CD pipelines should trigger alerts or block deployments if critical issues are found. Automate compliance checks and integrate secrets management tools to avoid exposing credentials in code or logs.
3. Implement Least Privilege Access Control
Design access control based on the principle of least privilege (PoLP). Start by defining roles and permissions narrowly—grant only the exact actions needed. Avoid over-permissioned service accounts or user roles.
Use centralized identity and access management (IAM) platforms to enforce access policies and support auditability. For fine-grained control, adopt attribute-based policies where access depends on user context (e.g., department, location, time of access). Enforce separation of duties (SoD) to prevent abuse of combined privileges.
Monitor access logs for anomalies, and set up automatic revocation of permissions for inactive users or expired roles. Regularly schedule access reviews and recertifications to ensure that permissions remain appropriate.
4. Conduct Regular Security Training
Security knowledge decays quickly if not reinforced. Tailor training programs to different audiences—developers need secure coding and code review practices, while operations teams need to know about hardening systems and detecting intrusion signs.
Include training on how to recognize phishing, social engineering, and other user-targeted attacks. Use real-world scenarios and incident case studies to illustrate impact and responses. Require completion of baseline training for onboarding and mandate annual refreshers.
Simulate attacks through red team exercises or phishing tests to identify human vulnerabilities. Debrief participants and use results to guide further training needs.
5. Perform Continuous Security Testing
Establish a testing regimen that spans static, dynamic, and interactive methods. SAST tools analyze code for common vulnerabilities (e.g., buffer overflows, SQL injection) before it’s compiled. DAST tools test running applications by simulating attacks in real time.
Interactive application security testing (IAST) tools combine the strengths of SAST and DAST by running in QA environments and analyzing runtime behavior. Run dependency scans to detect known CVEs in third-party libraries and containers.
Supplement automated tools with manual testing, such as security-focused code reviews and red team exercises. Track findings in issue trackers, assign severity levels, and integrate fixes into sprints. Include regression testing to verify fixes and prevent recurrence.
6. Adopt Defense-in-Depth Strategies
Build security layers across all architectural domains—network, host, application, and data. Use perimeter defenses like firewalls and VPNs, but don’t rely solely on them. Within networks, use segmentation and microsegmentation to isolate workloads and restrict lateral movement.
At the host level, apply endpoint detection and response (EDR) tools, harden operating systems, and enforce patch management. For applications, use WAFs, secure APIs, and runtime protection mechanisms. Encrypt data at rest and in transit using modern protocols like TLS 1.3 and AES-256.
Implement monitoring and alerting at each layer to detect anomalous behavior early. Ensure that all layers operate independently—if one fails, the others must continue protecting the system.
7. Establish Incident Response Plans
Develop an incident response (IR) plan that covers detection, containment, eradication, recovery, and post-incident analysis. Assign roles to individuals and create communication plans for internal stakeholders, regulators, and customers.
Integrate IR capabilities with SIEM systems and log aggregation tools to centralize detection and correlation. Establish playbooks for common attack types—ransomware, insider threats, data breaches—and test them regularly through tabletop and red team/blue team exercises.
Document every incident, including near misses, and update the IR plan based on lessons learned. Ensure backups are tested for restorability and stored securely to support recovery.