A04: Insecure Design

Insecure Design is a broad category of vulnerabilities that result from flaws in the design and architecture of an application. These are not implementation bugs, but rather a failure to incorporate security thinking into the design process.

Examples of Insecure Design

• Lack of Threat Modeling: Failing to identify and mitigate potential threats during the design phase.
• Inadequate Business Logic: Flaws in the application's business logic that can be exploited by an attacker.
• Poorly Designed Access Control: Access control mechanisms that are not granular enough or are easily bypassed.
• Failing to Separate Components: A monolithic design where a vulnerability in one component can compromise the entire system.

The Importance of Secure Design

• Proactive Security: Secure design is a proactive approach to security that aims to prevent vulnerabilities from being introduced in the first place.
• Cost-Effective: It is much cheaper to fix a security flaw during the design phase than it is to fix it after the application has been deployed.
• Reduces Attack Surface: A well-designed application will have a smaller attack surface, making it more difficult for an attacker to find and exploit vulnerabilities.

Shifting Left

The concept of "shifting left" refers to the practice of integrating security into the software development lifecycle (SDLC) as early as possible. By incorporating security into the design and development phases, you can significantly reduce the number of vulnerabilities in your application.

Insecure design is a reminder that security is not just about writing secure code, but also about designing secure systems.