Your Perimeter Extends Beyond Your Walls

You locked down your network. You patched your systems. You trained your people. You did everything right.

Then someone breached your vendor. And suddenly their problem became your problem.

The modern security perimeter is a lie we tell ourselves. We draw neat diagrams with firewalls at the edges and sensitive data in the middle. We implement zero trust architectures within our own four walls. We congratulate ourselves on our hardened infrastructure.

Meanwhile, your payment processor has access to customer data. Your cloud provider holds your encryption keys. Your managed service provider logs into your systems daily. Your contractors VPN into your network. Your SaaS vendors sync with your directories.

Each one of these relationships is a door. Each vendor's security posture becomes your security posture. Their vulnerabilities are your vulnerabilities. Their incidents are your incidents. Their breaches end up in your breach notification letters.

The worst part? You probably don't know how secure they actually are. You reviewed a compliance checklist during procurement. You got them to sign some contractual language about security standards. Maybe you even saw a SOC 2 report if you were thorough.

That tells you almost nothing about whether they'll be the vector for your next disaster.

Security Brutalism calls for a return to the fundamentals of security to build strong and more resilient defenses. The philosophy is a reaction to this very problem: the overuse of vendors and solutions that don't quite cut it but always add attack surface. We can't do everything without some vendors. The solution shouldn't be to cut them all completely, but rather be ruthlessly selective about who you bring in and how you assess them.

The solution is to stop pretending your perimeter ends at your infrastructure. Start treating vendor security as an extension of your own security program. That means continuous monitoring, not annual questionnaires. That means incident response plans that account for third-party compromises. That means having the hard conversations about access controls and data minimization before the contract is signed, not after the breach is disclosed.

When you think about your attack surface, include every vendor that touches your data or your systems. When you plan your security budget, include the resources needed to properly vet and monitor those relationships. When you run tabletop exercises, simulate the scenario where the breach starts at a trusted partner.

Your perimeter is everyone you trust. Start defending it that way.