From Ars Technica:
Meet PoisonTap, the $5 tool that ransacks password-protected computers
The perils of leaving computers unattended just got worse, thanks to a newly released exploit tool that takes only 30 seconds to install a privacy-invading backdoor, even when the machine is locked with a strong password.
PoisonTap, as the tool has been dubbed, runs freely available software on a $5/£4 Raspberry Pi Zero device. Once the payment card-sized computer is plugged into a computer's USB slot, it intercepts all unencrypted Web traffic, including any authentication cookies used to log in to private accounts. PoisonTap then sends that data to a server under the attacker's control. The hack also installs a backdoor that makes the owner's Web browser and local network remotely controllable by the attacker.
PoisonTap is the latest creation of Samy Kamkar, the engineer behind a long line of low-cost hacks, including a password-pilfering keylogger disguised as a USB charger, a key-sized dongle that jimmies open electronically locked cars and garages, and a DIY stalker app that mined Google Streetview. While inspiring for their creativity and elegance, Kamkar's inventions also underscore the security and privacy tradeoffs that arise from an increasingly computerized world. PoisonTap continues this cautionary theme by challenging the practice of password-protecting an unattended computer rather than shutting it off or, a safer bet still, toting it to the restroom or lunch room.
Once you have physical access to a machine, that machine is toast. There are many ways of hacking into a computer if you don't mind the victim knowing that someone has touched their machine. There are several ways (including this new one) to do it without their being aware.
