General Overview
Security should be an integral part of the SDLC, planned from the very beginning, rather than added as an afterthought. Many cyberattacks exploit software vulnerabilities—often due to programming mistakes or oversights—that leave applications, servers, or websites exposed. Development teams must build products and services with a high security standard to prevent such attacks.
A strategic security mindset requires:
- Organization-wide security policies, processes, and principles
- Continuous security training, especially for development teams
- Appropriate testing and monitoring tools
- Proactive integration of security in all phases of the product lifecycle, from inception to maintenance
Adopting these principles can help organizations switch from a reactive to a proactive approach.
Key Security Principles
1. Establish a Security Process
Secure products and services require a well-defined security process that covers design, coding, testing, deployment, fixing, and maintenance. Development teams should focus on preventing security bugs rather than spending excessive time fixing them later. Regular reviews of requirements, code, documentation, and tests are essential.
2. Consider Security as a Product Feature
Security must be treated as a core feature. If not explicitly outlined, security may be neglected, resulting in insecure products. Adding security later in the development process may require significant architectural changes, increasing complexity and costs. Ensure that security requirements and potential threats are part of the design and specifications.
3. Economy of Mechanism
Complex designs increase the likelihood of implementation errors. Security mechanisms should be kept simple, making them easier to implement, verify, and maintain. Simplicity reduces the potential for vulnerabilities.
4. Use Least Privilege
Applications should only execute with the minimal privileges necessary to perform their tasks. Limiting privileges reduces the potential impact of vulnerabilities. For example, running code with admin privileges exposes the system to greater risk. Always use the least privileged user or process to perform specific tasks.
5. Separation of Privilege
A protection mechanism that requires multiple conditions to grant access is more robust. Separation of privilege eliminates single points of failure. Two-factor authentication is a widely-used example, requiring “something you have” and “something you know” to gain access.
6. Minimize the Attack Surface Area
Every added feature increases the risk of security vulnerabilities. Minimize the functions exposed to users, reducing potential attack vectors. For instance, restrict access to sensitive functions, such as search features, to registered users only to lower the attack surface.
7. Use Defense in Depth
Layer security controls to approach risks from multiple angles. Instead of relying solely on a firewall, use additional controls like two-factor authentication, IP checks, CAPTCHA, and monitoring of login attempts. This ensures multiple layers of defense in case one is compromised.
8. Assume External Systems Are Insecure
Third-party services and external systems should never be trusted implicitly. Always validate data received from external sources and ensure those services are not granted high-level permissions. Treat all external input as potentially malicious until proven otherwise.
9. Plan for Failure
Systems will fail, and incidents will happen. Prepare for such failures by having security contingency plans in place. For example, know what to do if a firewall is breached or a website is defaced. Planning for failure ensures you can recover securely and effectively.
10. Fail Securely
When an application fails, it should not expose sensitive data or grant additional privileges. Failures should be handled securely, ensuring no sensitive information (e.g., database queries, logs) is leaked, and the system remains protected.
11. Employ Secure Defaults
Applications should be secure by default. For example, new users should have minimal privileges initially, with security measures in place that require intentional steps to obtain higher access. Default settings should ensure strong security policies, such as password complexity and expiration rules.
12. Avoid Security by Obscurity
Security should not rely on obscurity. Hidden information or functions (e.g., admin URLs) can easily be discovered by attackers. Ensure that adequate security controls exist without relying on hidden elements or obscured code.
13. Complete Mediation
Access rights should be validated on every access attempt, not based on cached decisions. Permissions may change over time, so rely on real-time checks to ensure secure access control.