Building vs Buying Security Infrastructure: The Real Trade-offs

I have built six security platforms from scratch: Presidio (XDR), Valta (CTI), Mirage (Deception), PhishSim (Phishing Simulation), a SOC portal, and a security assessment framework. I do it because I believe in control and customization. But I would be dishonest if I said building is always better than buying. The build vs buy decision for security infrastructure depends on specific factors, and the right answer changes for every organization.

When building makes sense

Building makes sense when: commercial solutions don't cover your specific use case (for Italian SMEs, enterprise XDRs were too expensive and too complex - this was the driver for Presidio), when you have internal expertise to maintain the system over time (building is easy, maintaining is hard), when vendor lock-in is a strategic risk (changing SIEM after 3 years of custom rules is extremely painful), and when deep customization is a requirement (generic SOAR playbooks don't work for every organization).

When buying makes sense

Buying makes sense when: you don't have a technical team to maintain the solution (an unmaintained Wazuh is worse than a managed service), when time-to-value is critical (implementing an XDR stack from scratch takes months, a managed service takes weeks), when compliance requires specific product certifications (some compliance frameworks require certified products), and when the total cost of ownership of build exceeds buy (and it happens more often than you think).

My approach is pragmatic: I build the core where customization is critical (detection rules, SOAR playbooks, deception), and use open source components where commodity is acceptable (SIEM engine, case management, visualization). I don't build a SIEM engine from scratch - I use Wazuh. But I build the integrations, playbooks, bridges, and customizations that transform individual components into a coherent platform. The real value is in integration and adaptation, not in rewriting what already exists.