A companion tool is a supporting application that helps software talk to another system, such as a database, API, or service. It may be a graphical interface, command-line utility, driver, connector, or framework integration. Unlike the core server, a companion tool usually runs on a developer workstation, application host, or administrator’s machine and translates user actions or application data into requests that the backend can understand.
In cyber security, companion tools matter because they often sit on trusted paths between users and sensitive systems. If they mishandle input, parse data unsafely, or expose dangerous features, they can become an attack surface even when the backend is hardened. Attackers may abuse these tools for query injection, command execution, or data tampering; defenders reduce risk by patching them, limiting privileges, and reviewing how untrusted input flows through connectors and admin interfaces.