🛡️OWASP 4 : Insecure Design

In today’s fast-paced digital world, applications are being developed at lightning speed. While agility is important, it often comes at the cost of secure design principles. Insecure Design, one of the OWASP Top 10 vulnerabilities, refers to flaws that arise due to weak or missing security controls in the architecture and design phase of an application.

Unlike coding mistakes or misconfigurations, insecure design reflects deeper issues with how the application was planned. If the foundation is weak, no amount of patches or quick fixes can make it truly secure.

What is Insecure Design?

Insecure Design refers to systemic design flaws that make an application vulnerable to exploitation. These flaws occur before a single line of code is written – during planning, architecture, and requirement gathering.

It is about not considering security early enough, or overlooking risks while creating workflows, business logic, or system models.

Key traits of insecure design:

• Missing or weak threat modeling.

• No enforcement of least privilege.

• Overly trusting user input.

• Flawed business logic leading to abuse.

• Lack of defense-in-depth strategies.
  

Types of Insecure Design

Here are some common categories:

1. Business Logic Flaws

• Allowing unlimited login attempts without lockout.

• Shopping carts that allow price manipulation.

• Missing validation in workflow steps.

2. Weak Authentication & Authorization Design

• Relying only on session IDs without expiration.

• Designing role-based access with excessive permissions.

• Failing to plan for MFA (Multi-Factor Authentication).

3. Inadequate Threat Modeling

• Ignoring potential abuse cases during design.

• No review of attack vectors for new features.

4. Lack of Secure Defaults

• New users get admin privileges by default.

• Application assumes input is always safe.

5. Insufficient Security Controls

• No rate limiting for sensitive operations.

• No encryption for sensitive data in transit or at rest.
  

Real-World Examples

1. Broken Business Logic in Banking App A banking app allowed fund transfers without checking daily limits. Attackers exploited this to move large sums, bypassing fraud detection.

2. E-commerce Price Manipulation An e-commerce platform didn’t validate cart prices on the server. Attackers modified the front-end request to buy items at $1 instead of $100.

3. Unlimited Login Attempts A SaaS platform lacked account lockout mechanisms. Attackers performed brute force attacks and compromised thousands of accounts.
   

Recommendations to Prevent Insecure Design

1. Adopt Secure Development Lifecycle (SDLC)

Integrate security checkpoints during requirement gathering, design reviews, and testing.

2. Perform Threat Modeling

Identify potential abuse cases, attack vectors, and data flow risks early in the design phase.

3. Enforce Strong Authentication & Authorization

• Apply least privilege principle.

• Use MFA where possible.

• Ensure session management is properly designed.

4. Implement Defense-in-Depth

• Apply rate limiting, CAPTCHAs, and monitoring for sensitive operations.

• Validate both client-side and server-side input.

5. Use Secure Defaults

• Set conservative permissions and security settings by default.

• Avoid relying solely on users to configure security.

6. Regular Design Reviews & Penetration Testing

Involve security teams in design walkthroughs and test logic flaws before deployment.

Conclusion

Insecure Design is one of the most dangerous yet overlooked vulnerabilities because it stems from flawed thinking at the earliest stage of development. Fixing insecure design later is costly, time-consuming, and often ineffective.

Organizations must prioritize security at the design phase, conduct thorough threat modeling, and apply robust security principles. By building applications on a strong foundation, businesses can significantly reduce the risks of exploitation and maintain user trust.