The stealthy Arduino-based device, dubbed "KeySweeper", looks and functions just like a generic USB mobile charger, but actually sniffs, decrypts, logs, and reports back all keystrokes from a Microsoft wireless keyboard.
"KeySweeper is a stealthy Ardunio-based device camouflaged as a wall charger that wirelessly sniffs, decrypts, logs and reports-back all keystrokes from any Microsoft wireless keyboard in the vicinity," Kamkar said.
The security researcher has also released instructions on how to build the USB wall charger online and surprisinglyits is cheap to build and quite capable. KeySweeper includes a web-based tool for live keystroke monitoring, capable to send SMS alerts for typed keystrokes, usernames, or URLs, and even continues to work after it is unplugged because of its rechargeable built-in battery.
"Even if we do not know the MAC address, we can decrypt the keystroke. Using a few-dollar Arduino and a US$1 Nordic RF chip we can decrypt these packets and see any keystroke of any keyboard in the vicinity that's using the Microsoft wireless keyboard protocol and it doesn't matter what OS is used."
Keysweeper stores the captured keystrokes both online and locally, and then send it back to the KeySweeper operator over the Internet via an optional GSM chip.
Usually, Microsoft wireless keyboards encrypt their data before sending it wirelessly, but Kamkar claims to have discovered several vulnerabilities in it that make the data easy to decrypt. Kamkar hasn't tested KeySweeper on every Microsoft wireless keyboard, but he believes that they will all be vulnerable.
Kamkar hasn't just outlined multiple vulnerabilities, but also released detailed instructions on how to build the device on GitHub. He's also produced a half-hour video on KeySweeper, which you can watch below:
