KeySweeper

Definition
A KeySweeper is

"a covert device that resembles a functional Universal Serial Bus (USB) enabled device charger which conceals hardware capable of harvesting keystrokes from certain wireless keyboards."

Overview
"If placed strategically in an office or other location where individuals might use wireless devices, a malicious cyber actor could potentially harvest personally identifiable information, intellectual property, trade secrets, passwords, or other sensitive information. Since the data is intercepted prior to reaching the CPU, security managers may not have insight into how sensitive information is being stolen."