USB redirection is a remote-session feature that forwards USB device activity over a network so a remote computer can treat the device as if it were locally attached. In practice, the remote desktop client or virtualization layer captures USB enumeration, input, storage, or vendor-specific control traffic and presents it to the host through a software channel.
This matters because USB is not just a connector; it is a trust boundary. When redirection is enabled, a remote session can expose Plug and Play, driver loading, and device-installation logic to untrusted hardware behavior, even when no physical access to the target machine exists. Attackers may abuse that path with emulated devices or malicious peripherals to trigger unintended installs or privileged actions, while defenders use the same feature carefully to support printers, smart cards, and other peripherals. Limiting redirection to approved device classes reduces risk.