No one decides one morning to make their information system complex. Complexity accumulates quietly: an exception here, one more tool there, a temporary integration that becomes permanent, a vendor added without retiring another. A few years later, no one can draw the real architecture on a whiteboard. That is precisely the moment complexity stops being an inconvenience and becomes a first-order security risk.
The rule is simple: you cannot secure what you do not understand. And the more complex a system is, the less it is understood — including by the people who built it.
Complexity is an attack surface, not an architecture detail
In cybersecurity, every additional component does not add a risk; it adds several. A new tool means an agent to keep updated, credentials to manage, an API to expose, a vendor to monitor, an integration to test. Risk does not grow linearly with the number of components: it grows with the number of interactions between them, which itself rises almost exponentially.
- Problem: every interconnection is a door. The more there are, the more impossible it becomes to lock them all — or even to list them all.
- Impact: blind spots multiply. The misconfigured firewall, the forgotten service account, the mailbox forwarding rule left in place, the cloud instance spun up for a test and never destroyed — each one an asset no one watches because no one knows it exists.
- Action: treat complexity reduction as a security control in its own right, on par with encryption or MFA. What does not exist cannot be attacked.
Attackers understand this perfectly. They are not looking for your best defense, they are looking for your most forgotten component. The "living off the land" campaigns we covered recently exploit exactly this: legitimate tools, already present, drowned in an environment too large to monitor in full.
The real costs of complexity
Complexity is not only paid for on the day of the incident. It levies a permanent tax, often invisible in the budget.
- Cognitive cost. When the architecture exceeds what a team can hold in their heads, decisions get made on faulty mental models. People fix the wrong component, duplicate a function that already exists, or assume a system is isolated when it no longer is.
- Detection cost. The more signals, logs and alerts there are, the more the useful signal drowns in noise. A SOC receiving 50,000 alerts a day does not detect better than one receiving 500 targeted ones — it detects worse, because alert fatigue makes the real incident look like one more false positive.
- Response cost. In a crisis, complexity stretches every minute. Identifying the affected systems, understanding the dependencies, knowing what you can cut without breaking everything — all of it takes time you do not have when ransomware is encrypting your backups.
- Compliance cost. You cannot attest to a control over a perimeter you do not master. Every exception, every "special" system, every waiver becomes one more line to document, justify and defend in front of an auditor.
- Human cost. Complexity burns teams out. The best engineers leave when they spend more time understanding what exists than building what is next. And the departure of the one person who "was the only one who knew" is, in itself, a vulnerability.
Why complexity accumulates (and why it is so hard to reverse)
Understanding the mechanism helps you fight it. Complexity thrives because adding is always easier than removing.
Adding a tool solves a problem you can see today. Removing a tool requires proving it is no longer useful to anyone — a far heavier burden of proof, and work no one is rewarded for. So the layers pile up. Every acquisition, every reorg, every "quick fix" leaves a sediment that no one later dares to dismantle, for fear of breaking something invisible.
Complexity also carries a political bias: a complicated system gives the illusion of robustness and protects the few who are its sole keepers. Simplifying therefore takes managerial courage as much as technical skill.
Best practices to detox your IT
Reducing complexity is not a one-off project; it is a discipline. Here are the practices that make the difference.
Map before you simplify. You cannot reduce what you cannot see. Build a real, continuous inventory of your assets — exposed and internal alike. An external attack surface management (EASM) effort routinely surfaces dozens of forgotten systems your official diagrams never showed. The first win is not securing those assets — it is discovering they exist.
Adopt a "complexity budget." Like technical debt, complexity needs a conscious ceiling. Impose a simple rule: every new tool or vendor added must come with the identification of a component to retire, or an explicit justification for why the balance is rising. The goal is not zero complexity — it is complexity that is chosen rather than inherited.
Standardize ruthlessly. Three solutions that do the same thing mean three times the attack surface, three update cycles, three teams to train. Converge on standards: one identity provider, one hardening baseline, one log format, one review process. Accidental diversity is a debt; uniformity is a security control.
Shrink your vendor estate. Every third party is an extension of your attack surface that you do not directly control — as the cascading breaches at shared providers keep reminding us. Fewer vendors means fewer questionnaires, fewer integrations, fewer supply chains to watch. Streamline your third-party risk management by consolidating where you can and removing dormant access.
Decommission actively. Put a formal end-of-life process in place: when a project ends, when an employee leaves, when a contract expires, the associated assets must be identified and destroyed. An asset with no owner is an asset with no defender.
Prefer boring. In security, "boring" technology — proven and well understood — almost always beats the shiny new thing. Every innovation you introduce must pay its complexity cost with clearly superior value. The question is not "is this new tool better?" but "is it enough better to justify the surface it adds?"
Measure complexity, or it goes invisible again. Track a few indicators: number of exposed assets, number of vendors with data access, number of open security exceptions, median age of unpatched systems. What is not measured always drifts upward.
Simplicity is a strategic decision
Simplicity does not happen by accident. It is the result of constant, often uncomfortable trade-offs where you refuse the easy addition in favor of durable clarity. It is a leadership responsibility as much as an engineering one: an executive committee that demands visibility, risk metrics and clear prioritization creates the conditions for teams to dare to simplify.
Complexity is the attacker's playground. Clarity is your defensive edge. Reducing the first increases the second — and it is, concretely, one of the highest-return security decisions you can make.
If you want to see what that clarity looks like — a mapped attack surface, prioritized risks, vendors under control in a single view — the product tour shows how we turn exposure into prioritized action.