Humans in Security

Intuition and Critical Thinking

Despite advances in frameworks, automated scanners, AI Threat Detection and compliance checklists, truly secure software systems are still rare. The reason is simple: security cannot be solved by tools alone. It requires a high level of human intuition and critical thinking.

Security Is About Anticipating the Unknown

At its core, software security is a human problem. Without harmful intent, a software vulnerability can go unnoticed and not be exploited. Intention is the key differentiator here. The engineers involved in designing  a secure system need to have the ability to think like a person with malicious or harmful intent to truly build a secure system. This paradox is what makes security hiring challenging. The people that are considered to be ‘safe’ enough to be trusted to secure a system should also identify ways to attack the system and build the rails to safeguard the system and data.

Designing secure systems therefore requires engineers to ask uncomfortable questions:

• What if this assumption is wrong?

• What happens if this component is misused, not used as intended?

• How could someone abuse this feature in a way we never planned for?

Answers to these questions rely heavily on intuition developed through experience, curiosity, and the ability to mentally simulate how systems behave under stress or misuse.

Critical Thinking Over Checklists

Security standards and best practices—such as OWASP Top 10, ISO 27001, or SOC 2—are valuable. But they are guardrails, not guarantees. Following a checklist can ensure baseline hygiene, but it cannot ensure resilience against novel attacks.

Critical thinking  is what bridges this gap. It allows engineers to:

• Understand why a control exists, not just that it exists

• Evaluate trade-offs between usability, performance, and risk

• Recognize when a “secure-by-default” setting is insufficient for a specific context

For example, encryption is often treated as a box to check. Critical thinking asks deeper questions: Where are keys stored? Who has access? What happens during backups, logging, or error handling? Many real-world breaches occur not because encryption was absent, but because it was applied without thoughtful system-level reasoning.

Intuition is really heightened consciousness

Secure design demands seeing the system as a whole rather than as isolated components. A single microservice may be secure in isolation, yet introduce vulnerabilities when combined with others.

Intuition helps engineers spot patterns such as:

• Privilege escalation paths across services

• Trust boundaries that exist in diagrams but not in reality

• Implicit dependencies created by shared infrastructure or credentials

This intuition is built over time by studying past failures, threat models, and real incidents. Engineers who think like attackers—without becoming reckless—are better equipped to defend systems effectively.

Threat Modeling Is a Thinking Exercise, Not a Template

Threat modeling is often misunderstood as a formal document or meeting. In reality, it is a continuous thinking process. The most effective threat modeling happens informally and repeatedly, during design discussions and code reviews.

This process relies on critical thinking skills such as:

• Identifying assets worth protecting

• Understanding attacker motivations and capabilities

• Evaluating the impact and likelihood of different attack paths

No tool can fully automate this reasoning. It requires judgment, context awareness, and sometimes gut instinct informed by experience.

Secure Design Is About Making Fewer Assumptions

Many security failures trace back to unchecked assumptions:

• “This endpoint will only be called internally.”

• “Users won’t try to manipulate this input.”

• “This data isn’t sensitive.”

Intuitive engineers learn to challenge these assumptions early. They recognize that every assumption is a potential vulnerability. Critical thinking helps turn vague concerns into concrete design decisions, such as enforcing explicit trust boundaries, validating inputs rigorously, or minimizing data exposure by default.

The Human Element Remains Irreplaceable

AI tools, static analysis, and automated testing have significantly improved security posture across the industry. However, they excel at finding known patterns, not inventing new ones. Attackers, on the other hand, are constantly inventing.

Designing secure software systems therefore remains a fundamentally human challenge. It demands creativity to imagine misuse, discipline to question convenience, and critical thinking to balance competing constraints.

Secure software design is not just about writing correct code—it is about thinking correctly. It requires intuition to anticipate threats that have never occurred before and critical thinking to evaluate risks beyond what tools and checklists can capture.

As systems grow more complex and interconnected, the engineers who can think deeply, question assumptions, and reason holistically will be the ones who build software that truly stands the test of time—and attack.