Security of supply is the assurance that essential components, services, and support will keep arriving reliably when they are needed. In cybersecurity, this matters because defenders depend on a steady flow of hardware, software, updates, spare parts, cloud capacity, and specialist services. If that flow breaks, organizations may be left with unpatched systems, delayed replacements, or unavailable monitoring and response tools.
Attackers can exploit weak supply chains by disrupting vendors, tampering with software builds, or targeting logistics and support channels. Defenders use security-of-supply controls to reduce that risk: multiple suppliers, inventory planning, secure procurement rules, signed software updates, trusted distribution paths, and continuity plans for critical services. The goal is not just availability in normal operations, but resilience when political pressure, sanctions, outages, or malicious interference threaten delivery.