A repository manager is software that stores, proxies, and organizes application artifacts and dependencies. It sits between developers, build systems, and external package sources, handling requests for libraries, container images, plugins, and other build inputs. By caching content and controlling access, it helps teams build reproducibly and avoid direct dependence on every upstream repository.
In cyber security, repository managers are high-value supply-chain targets because they influence what code gets downloaded and trusted during builds. If compromised or misconfigured, they can expose credentials, serve malicious packages, or become a pivot point into internal networks. Defenders treat them as critical infrastructure: patch them quickly, isolate them from sensitive networks, enforce strong authentication, verify package integrity, and monitor unusual repository activity, admin changes, and outbound traffic.