Dependency visibility is the ability to identify and track the external components a system relies on, such as libraries, packages, APIs, build tools, cloud services, and third-party integrations. It gives defenders a map of what is inside the trust boundary and what is brought in from outside.
This matters because attackers often exploit hidden or poorly managed dependencies to reach many victims through one compromise. If an organization cannot see which components it uses, it cannot reliably patch them, verify their integrity, or assess the blast radius when a supplier is breached. In real defenses, dependency visibility supports software inventory, software bills of materials, package monitoring, and alerts for risky version changes. In attacks, weak visibility can let malicious updates, tampered libraries, or compromised service accounts spread through routine workflows before anyone notices. Good visibility turns supply-chain security from guesswork into control.