KiwiSDR is hardware that uses a software-defined radio to monitor transmissions in a local area and stream them over the Internet. A largely hobbyist base of users does all kinds of cool things with the playing-card-sized devices. For instance, a user in Manhattan could connect one to the Internet so that people in Madrid, Spain, or Sydney, Australia, could listen to AM radio broadcasts, CB radio conversations, or even watch lightning storms in Manhattan.
On Wednesday, users learned that for years, their devices had been equipped with a backdoor that allowed the KiwiSDR creator—and possibly others—to log in to the devices with administrative system rights. The remote admin could then make configuration changes and access data not just for the KiwiSDR but in many cases to the Raspberry Pi, BeagleBone Black, or other computing devices the SDR hardware is connected to.
A big trust problem
Signs of the backdoor in the KiwiSDR date back to at least 2017. The backdoor was recently removed with no mention of the removal under unclear circumstances. But despite the removal, users remain rattled since the devices run as root on whatever computing device they’re connected to and can often access other devices on the same network.