Companion software is the application bundled with a hardware device to configure it after installation. It is often used to set macros, lighting, sensitivity, firmware options, or other device-specific features that the operating system does not expose directly.
In cyber security, companion software matters because it becomes part of the device’s trust chain. If the app is buggy, outdated, or distributed through an untrusted channel, it can create support problems, weaken security posture, or even open the door to malicious updates and configuration tampering. Attackers may target these tools to change device behavior, persist across reboots, or abuse privileged drivers. Defenders look for signed updates, least-privilege installation, transparent settings storage, and a recovery path if the software is unavailable. In practice, a peripheral may be safe as hardware but still difficult to manage if its companion app is missing, platform-limited, or compromised.