Back in July, we wrote about a massive security hole -- BadUSB -- that potentially gave hackers the ability to hijack or subvert billions of USB devices, from keyboards to printers to thumb drives. At the time, due to the severity of the issue, the researchers who discovered the flaw didn't publish their BadUSB exploit code. Now, however, two other hackers have worked out how to exploit BadUSB -- and they've published their code on Github for all to see.