There was a time, not particularly long ago, when securing a computer required little more than a locked door and perhaps a trusted guard at the front desk. The machines were physically imposing, access was inherently local, and threats were tangible rather than virtual. If someone couldn’t enter the room, they simply couldn’t access your data. This was security, rudimentary yet effective for the era. And yet, when we look back, we begin to see the earliest contours of what would eventually become the history of cybersecurity — shaped more by trust and convenience than by threat models or adversarial design.
Reflecting on this period feels almost surreal from the vantage point of today’s complex digital landscape. We now operate in a world where credential theft is a thriving industry, attack surfaces appear and vanish in moments, and trust is negotiated—or broken—in fractions of a second. To grasp how we arrived at such complexity, it helps immensely to revisit where we began.
The Air-Gapped World
In the earliest days of computing, security didn’t revolve around firewalls or endpoint detection—such concepts were decades away. Instead, the barriers were physical, tangible, and immediate: keys made of brass, thick doors, and punch cards. Access control was physical control. The very idea of remote intrusion was, quite literally, unthinkable.
Even as computing evolved toward multi-user systems, security measures remained comparatively primitive. MIT’s Compatible Time-Sharing System (CTSS), a revolutionary step toward today’s shared computing environments, introduced the concept of individual user accounts—and, by extension, the password. But passwords themselves were almost an afterthought. In 1966, researchers famously discovered that the system’s entire password file could be printed out in plain text—no encryption, no hashing, and certainly no salting. Passwords were simply a convenience, not a robust security measure.
This vulnerability wasn’t born of negligence or malice but rather from innocence and novelty. The idea that someone might deliberately seek to compromise a computer system was still beyond imagination. Threat actors had yet to emerge as a professional class. In that moment, curiosity still eclipsed commerce, and trust was freely given—not because people were naïve, but because they had no reason yet to be suspicious.
Password Prompts and Perimeter Thinking
By the 1980s, computing had shifted from centralized mainframes to networks of personal computers, dramatically reshaping how we thought about security. Complexity increased, though sophistication lagged behind. Passwords became ubiquitous. Antivirus solutions entered the market. Yet despite these incremental improvements, the underlying security model remained stubbornly simplistic, centered on a clear distinction between “inside” and “outside.”
Within the perimeter, users were implicitly trusted—viewed as benign by default. Outside, every connection was treated with suspicion and blocked by firewalls or carefully regulated via VPN tunnels. This castle-and-moat approach defined corporate security for decades. It functioned adequately in an environment defined by stable boundaries, predictable workflows, and consistent endpoints.
But inherent fragility lurked beneath this seemingly robust facade. Once an attacker found a foothold inside the trusted zone, the entire internal network was often compromised. As the nature of work evolved—remote employees logging in from cafes, Wi-Fi permeating every corner, SaaS applications bypassing traditional firewalls—the concept of a secure, clearly defined perimeter rapidly became untenable.
Yet even today, many security practices remain rooted in these older assumptions, shaping policy decisions, architectural designs, and even user behavior in subtle, often problematic ways. The fortress model endures, not because it’s effective, but because its underlying logic feels intuitively comfortable, even if that comfort is largely illusory.
What We Overlooked
Security, in those days, was often a byproduct of circumstance rather than intention. Obscurity acted as a shield. Trust was implicit. Convenience usually won out over caution. These weren’t reckless decisions — just deeply human ones, shaped by a context in which malevolent actors were still more theoretical than real.
But that illusion didn’t last.
In 1988, the Morris Worm crawled its way through the early internet. Not crafted by a cybercriminal syndicate or state actor, but by a graduate student experimenting with code. The result? A self-replicating denial-of-service that crippled thousands of machines. It wasn’t the first sign that our systems were vulnerable, but it was the first to make headlines — and it shattered the quiet assumption that harm would always be intentional, or rare.
The decades that followed were marked by a reactive posture. Security was implemented piecemeal, often after the fact. Virus definitions updated weekly. Patches applied in hindsight. And almost without fail, security controls were seen as something to be circumvented — an obstacle to workflow, a nuisance to be disabled “just this once.” The larger lesson, rarely acknowledged, was that most systems weren’t designed with threat in mind — they were designed with trust in mind. That was their brilliance. And their flaw.
The Legacy We Inherited
So much of today’s breach activity traces directly back to an earlier era’s assumptions. Flat network topologies. Overprivileged accounts. Shared administrator credentials passed around like tribal knowledge. These patterns weren’t malicious in origin — just expedient. But they’ve proven remarkably durable, and remarkably dangerous.
We’re still contending with infrastructure designed in the absence of internet-native thinking. Windows NT boxes quietly humming under the weight of critical workloads. Core systems without MFA. Legacy provisioning scripts still deciding who has access to what, decades after their authors have moved on — or retired.
The term “legacy” often evokes something quaint or fragile, like an artifact in a museum. But in security, legacy is far less benign. It’s not just old code or unsupported platforms — it’s habit. It’s institutional memory calcified into configuration. It’s the quiet persistence of “this is how we’ve always done it,” even when the stakes have changed.
And despite everything we now know — about supply chain risk, credential compromise, and lateral movement — the past remains uncomfortably present. Walk into any enterprise with a sprawling Active Directory forest and you’ll feel it immediately: the architecture may be cloud-adjacent, but the bones are pre-web. We haven’t outgrown the problem. We’ve just gotten better at abstracting it. We’ve layered on Kubernetes and Terraform and ephemeral workloads, but the foundation — and the flaws — remain stubbornly intact.
Looking Ahead
Security, for most of its history, has matured in the aftermath of failure. We build walls only after someone walks through the open door. We harden systems in the wake of compromise. That’s not a judgment — it’s an honest reflection of how most disciplines evolve: slowly, reactively, painfully.
But if we understand where our assumptions came from — and why they no longer hold — we can begin to do better. We can honor the brilliance of early design without replicating its blind spots. And we can resist the all-too-human tendency to solve new problems with old frameworks simply because they feel familiar.
The threats have changed. The technology has changed. The context, the velocity, the stakes — all of it is different. But the question at the heart of it all remains stubbornly the same:
How do we protect what matters, in a world where everything is connected, and nothing stays still?
In the next piece, we’ll turn to the age of firewalls and fortress thinking — and trace how the castle model came to define a generation of security architecture, for better and, eventually, for worse.
