Dependency mapping is the practice of documenting how systems, vendors, applications, APIs, identities, and data flows depend on one another. A good map shows not just direct connections, but also hidden links such as shared cloud services, authentication providers, third-party software, and backup paths. In cyber security, this matters because the real impact of an incident often depends on what the affected system supports.
Attackers exploit dependencies to widen their reach. A compromise in one service can disrupt logins, payments, data sync, or recovery tooling if those services are tightly coupled. Defenders use dependency mapping to estimate blast radius, prioritize patching, segment networks, test failover, and plan incident response. It is especially important for AI deployments, where models, prompts, data stores, and pipelines may create new failure points. Without accurate dependency mapping, teams may fix the visible problem while the real operational risk remains elsewhere.