Device control is a security policy layer that decides which external devices can connect to a system and what actions they are allowed to perform. It typically governs USB drives, smartphones, cameras, printers, Bluetooth adapters, and other peripherals. Rules may allow, block, read-only access, or require encryption and logging before data transfer is permitted.
It matters because removable media is a common path for both malware ingress and data exfiltration. A compromised USB device can introduce malicious files, while an authorized drive can still be used to copy sensitive data out of an environment. In practice, device control supports defense by reducing attack surface, enforcing least privilege, and creating audit trails that show what was attached, transferred, and when. It is often paired with endpoint protection and data loss prevention to keep user convenience from becoming a security gap.