Supply-chain disruption is an interruption of the external suppliers, services, or dependencies that an organization relies on to operate. In cyber security, this can include cloud providers, software vendors, managed service providers, telecoms, payment networks, hardware logistics, or even identity and backup services. When one of these links fails, the impact can spread well beyond the original problem and affect availability, recovery, or business continuity.
It matters because many attacks now target the weakest outside dependency rather than the main victim directly. A compromised vendor update, a disabled support platform, or an outage at a critical third party can create the same operational damage as a direct intrusion. Defenders reduce this risk by mapping dependencies, checking supplier security, planning manual fallbacks, testing recovery assumptions, and avoiding concentration on a single provider. In practice, supply-chain disruption turns cyber risk into an enterprise resilience issue.