2021 OWASP Top Ten: Insecure Design

Insecure Design: Understanding Security Risk #4

Introduction to Insecure Design

• John Wagner introduces the topic of insecure design as the fourth security risk in the 2021 OWASP Top 10 list, emphasizing its focus on design and architectural flaws.

• The concept of "shift left" in security is discussed, highlighting the need to address security concerns even before coding begins.

Characteristics of Insecure Design

• Insecure design differs from insecure implementation; a secure design can still lead to vulnerabilities if not implemented correctly.

• An insecure design cannot be rectified by perfect implementation, indicating that foundational issues must be addressed at the design stage.

Practical Example: Movie Ticket Application

• Wagner presents a scenario involving a movie theater's online ticket purchasing system, illustrating how an attacker could exploit an insecure design.

• He explains how an attacker could reserve multiple tickets without payment due to flawed application logic, effectively blocking legitimate users from purchasing tickets.

Analogy: House Design Flaw

• A house analogy is used to explain insecure design; having a locked front door is ineffective if there’s an open entryway elsewhere.

• This analogy reinforces the idea that no amount of security measures can compensate for poor foundational designs.

Importance of Secure Development Practices

• Secure software development requires a secure development life cycle and continuous evaluation of threats throughout the project.

Understanding Secure Design in Applications

Importance of Threat Modeling

• Effective threat modeling is crucial for ensuring that all critical flows within an application are resistant to potential threats. It plays a significant role in secure design.

• When discussing secure design, it’s essential to compile both use cases and misuse cases for every tier of the application to identify vulnerabilities.

Use Cases vs. Misuse Cases

• Testing should not only confirm that the application functions correctly (e.g., selling tickets online) but also consider misuse scenarios where attackers might exploit weaknesses.

• An example of a misuse case includes an attacker group purchasing just below the threshold required for making a deposit, highlighting the need for comprehensive testing strategies.

Security Risks in OAuth

• The discussion emphasizes that insecure design is one of the top security risks identified in the OAuth Top 10 list, underscoring its significance in modern applications.