Security by design is an approach to building applications that incorporates cybersecurity into every phase of the software development lifecycle (SDLC). It involves identifying and addressing vulnerabilities before production to ensure a proactive AppSec strategy.
In the context of web applications, security by design shifts the focus from reactive measures to building secure systems from the beginning. It is a step towards integrating security into the software foundation, which includes effective threat mitigation.
Development vs. security
Traditionally, security and development processes have to find trade-offs, but these can be difficult. Developers tend to prioritize new functionality, while security takes a back seat. However, implementing this approach can lead to successful cyberattacks.
Instead, “secure by design” means that security requirements are built in from the start. Developers and security teams work together early on to both innovate and meet requirements while protecting sensitive information.
7 Principles of Security by Design
1. “Security as Code”
When teams can automate security policies and embed them into CI/CD pipelines, they have more scalable and effective risk management. With infrastructure-as-code (IaC) tools, configurations can be tested, deployed securely, and version-controlled.
2. Secure defaults
Systems should default to the most secure configurations possible. For example, this includes strong passwords, using HTTPS, and preventing excessive access. When teams can minimize the need for manual intervention, secure configurations reduce human error and improve risk management.
3. Least privilege principle
Users and systems should only have the permissions they need to perform their tasks. Implementing the principle of least privilege helps protect sensitive information and prevent data leaks due to security issues.
4. Segregation of responsibilities
Segregating responsibilities reduces the risk of abuse or errors. For example, multiple people or systems may be required to approve critical actions, such as when implementing changes in production.
5. Reducing the attack surface
Every function, endpoint, or service is a potential attack point. By limiting them, it can be made much harder for attackers to exploit vulnerabilities. This includes removing deprecated APIs, closing unnecessary ports, and removing unneeded features.
6. Validating access requests
Every access request should be validated every time. It is important to use controls that evaluate detected threats and avoid caching access rights. This helps the team to ensure that changes to roles or privileges are implemented quickly and efficiently.
7. Proper behavior when failing
When systems fail, they should default to a secure state. For example, if an authentication error occurs, access should be denied rather than granted. This ensures that unexpected issues do not impact overall security.
Security by design and proactive defense with DAST
Dynamic Application Security Testing (DAST) plays a critical role in achieving secure software development by identifying vulnerabilities in running applications. Unlike SAST, which tests the code itself, DAST can simulate real-world attacks by analyzing the application and how it behaves during execution.
This approach follows security best practices and helps developers identify vulnerabilities that can only be discovered when the application is running, such as misconfigurations, authentication weaknesses, or input validation issues.
The role of DAST in security by design
The principle of security by design and DAST go hand in hand, as dynamic testing examines the attack surface of an application during development and in production, contributing to a proactive AppSec approach.
Minimizing the attack surface
DAST tools identify vulnerabilities by testing application interface, APIs, and endpoints. This allows developers to address vulnerabilities and reduce the attack surface (for example, by removing problematic APIs if they are no longer needed) before attackers discover them and perform cyberattacks.
Additionally, the Invicti (formerly Netsparker) DAST platform can provide functionality to detect APIs and forgotten websites available on the Internet, allowing teams to control the organization’s attack surface.
Correct behavior during failure
Testing how a web application behaves under various failure scenarios is a key feature of DAST. These tools simulate conditions such as unexpected input or server errors to verify that the website is working as expected and enters a secure state. For example, denying access or providing general error messages that do not reveal sensitive information.
Secure defaults and the least privilege principle
DAST identifies misconfigurations, such as excessive permissions or unsafe defaults, that can lead to successful attacks. For example, the tool can look out for configurations that bypass authentication requirements.
Proactive protection through regular testing
Incorporating DAST and coding standards into a development pipeline enables teams to detect and fix vulnerabilities in near real-time. Here’s how proactive testing with DAST improves software security:
Early vulnerability detection
When DAST is integrated into CI/CD pipelines, builds can be automatically scanned before deployment. This proactive approach helps identify vulnerabilities faster and saves resources by eliminating the root cause of potential data leaks.
Realistic attack simulation
DAST mimics the behavior of attackers, attempting to use exploits such as SQL injections, cross-site scripting (XSS), and others. This allows teams to understand how a website will perform in the face of real-world threats.
Comprehensive coverage
DAST detects issues with authentication, session management, and data processing that other tools may miss.
Best practices for using DAST in developing secure software
Early Implementation
It is important to embed DAST into the software development lifecycle (SDLC) to ensure continuous monitoring and testing at various stages.
Combining DAST with other tools
DAST can be used in conjunction with SAST (Static Application Security Testing) and IAST (Interactive Application Security Testing) to achieve full coverage and reduce the likelihood of a breach. This combination allows organizations to identify vulnerabilities both in the code and at runtime.
Prioritizing remediation
DAST solutions often provide information about the severity level of the vulnerabilities found. This enables specialists to focus on fixing the flaws that pose the greatest risk to assets.
Team training
It is important to train developers to properly analyze and interpret DAST scan results, as well as to apply security by design principles when fixing vulnerabilities. This helps to increase knowledge and improve the team.
Strengthening proactive defenses
By using DAST in software development, organizations can move from a reactive to a proactive approach to security. This allows vulnerabilities to be identified and fixed during development rather than after an attack, allowing companies to create secure applications.
