BadUSB is a computer security attack using USB devices that are programmed with malicious software. For example, USB flash drives can contain a programmable Intel 8051 microcontroller, which can be reprogrammed, turning a USB flash drive into a malicious device. Karsten Nohl stated: "It's the struggle between simplicity and security. The power of USB is that you plug it in and it just works. This simplicity is exactly what's enabling these attacks."