The Blueprint Inspection Analogy

Imagine you're building a house. Would you rather have an inspector point out that your foundation design won't support a second floor before you pour the concrete, or after you've built the entire structure and it starts cracking?

The answer is obvious when we talk about construction. Yet in software development, we often skip the architectural review and hope our "building" doesn't collapse under the weight of security threats.

The reality is stark: Retrofitting security into an application after development can cost 6-10 times more than building it in from the start. But does security review during design and architecture actually identify potential vulnerabilities? Let me walk you through how and why it works.

How Design Reviews Catch Vulnerabilities

A design and architecture review helps certify the security-related features of your application before you write the first line of code. Think of it as a structured interrogation of your blueprints.

Here's the key insight: Security reviewers don't look at code—they ask questions.

These questions are carefully constructed based on known vulnerability patterns. When your development team answers them honestly, alongside supporting functional and technical documents, a skilled reviewer can predict where your application will be vulnerable.

The Power of the Right Questions

Let me give you some examples that illustrate how seemingly simple questions reveal deep security implications:

"Do you restrict the number of failed login attempts?"

This isn't just a yes/no question. The answer reveals whether your application is protected against dictionary attacks, credential stuffing, and brute-force attempts. If the answer is "no" or "we haven't thought about it," you've just identified a vulnerability before writing any authentication code.

"Do you validate inputs?"

Most developers say "yes" automatically. But the follow-up questions matter: Which inputs? What about hidden form fields? Cookie values? Stored secrets?

Applications commonly validate what users type into visible fields but completely miss the data traveling behind the scenes. This gap is where SQL injection and cross-site scripting attacks thrive.

"Do you develop your own cryptography?"

If the answer is yes, alarm bells should ring. Cryptographic algorithms are extraordinarily difficult to get right. Even seasoned cryptographers spend years perfecting these systems. Custom crypto almost always results in weaker protection than battle-tested platform services.

The Security Debt Compound Interest

Here's an analogy that resonates with anyone who's dealt with technical debt: Security debt compounds like interest on a loan.

A design flaw that would take 2 hours to fix during architecture review might take:

• 8 hours during development
• 32 hours during testing
• 128+ hours after production deployment (including incident response, patches, and reputation damage)

The cost doesn't just double—it multiplies. And unlike financial debt, security debt can suddenly become "due" when an attacker exploits that vulnerability you never addressed.

Making It Practical: The STRIDE Approach

One framework that makes design reviews actionable is STRIDE, which examines your architecture for six threat categories:

• Spoofing identity – Can someone pretend to be another user?
• Tampering with data – Can data be modified in transit or at rest?
• Repudiation – Can users deny actions they performed?
• Information disclosure – Can sensitive data leak?
• Denial of service – Can the system be overwhelmed?
• Elevation of privilege – Can users gain unauthorized access?

Walking through each component of your architecture with these questions creates a systematic security checklist. It's not magic—it's methodical thinking applied before you're committed to a particular implementation.

What You Need for an Effective Review

A successful architecture review requires:

1. Architecture diagrams – How components connect, where data flows
2. Trust boundary documentation – Where does your code trust external input?
3. Data classification – What's sensitive? PII? Financial data? Credentials?
4. Integration points – Third-party services, APIs, databases
5. Honest answers – The review only works if teams don't hide uncomfortable truths

The Bottom Line

Security review during design isn't a luxury or bureaucratic overhead—it's the most cost-effective security investment you can make. By spending time analyzing architecture and design documents, you're essentially buying insurance against expensive production vulnerabilities.

The questions may seem simple. The documents may seem tedious. But catching a SQL injection vulnerability in a design document costs you an hour of discussion. Catching it after a breach costs you customers, reputation, and potentially millions in damages.

Start asking the hard questions before you pour the concrete.