As the popularity of IoT devices grow, it’s only natural that security holes in some of the systems will become apparent. IoT Devices May Be Susceptible to Replay Attacks with a Raspberry Pi and RTL-SDR Dongle andAttack Some Wireless Devices With A Raspberry Pi And An RTL-SDR articles tell that an easy way to make a wireless replay attack attack against RF controlled devices is demonstrated on rtl-sdr.com, As RTL-SDR shows us that all you need to record and replay the 433MHz modulation signal is a Raspberry Pi, one of the RTL-SDR dongles (for software-defined radio), and a wire for an antenna (you don’t need to build special hardware like 433.92MHz OOK frame cloner).
The folks at RTL-SDR.com put up a guide to recording these open data bursts on a Raspberry Pi and playing them back by transmitting them from the Pi itself.Tutorial: Replay Attacks with an RTL-SDR, Raspberry Pi and RPiTX tutorial shows how to perform replay attacks on simple OOK modulated 433 MHz ISM band devices using an RTL-SDR dongle and RPiTX. The RTL-SDR will be used to record an AM audio file of the signal, and then RPiTX software will do it’s magic to transform that recording into a file that can be transmitted back on the same frequency via one of the Raspberry Pi’s GPIO pins. The article has ha nice Replay Attacks at 433 MHz with RTL-SDR and a Raspberry Pi running RPiTX video that shows how it works:
The video shows how to perform a simple record and replay attack on 433 MHz ISM band devices using nothing more than an RTL-SDR and Raspberry Pi. The Raspberry Pi runs RPiTX which allows it to transmit from a GPIO port with just a wire attached. No extra transmitter hardware is required.
For RF signal experimenters those tools allow much more than just replaying remote control signals. RPiTX Turns Rasberry Pi into Versatile Radio Transmitter few years back article tells that using just an appropriately-sized wire connected to one of the GPIO pins, the Raspberry Pi is capable of broadcasting using FM, AM, SSB, SSTV, or FSQ signals. This greatly increases the potential of this simple computer-turned-transmitter and anyone should be able to get a lot of use out of it. Transmitting FM, AM, SSB, SSTV and FSQ with just a Raspberry Pi tells that PiTx is a software which permit to transmit HF directly through a pin of Raspberry Pi GPIO. Unlike PiFM which transmit only in FM, PiTx is able to perform multi modulation (FM,AM,SSB,SSTV,FSQ) : it has an I/Q input to be agnostic.Pitx is now a real TRANSMIT SDR at very low cost. Be aware that it generate lot of harmonics (you need to add filtering to pass radio regulations – there is a Pi shield for that). Here is PiTxSDR video:
Building a Ham Transceiver with an RTL-SDR, Raspberry Pi and Rpitx about a Qtcsdr sotware that runs on the Raspberry Pi and interfaces with an RTL-SDR dongle and RpiTx to create a simple transceiver radio. As always with this type of thing only transmit if you are licensed and take care with the transmitted distance and filter the antenna output when transmitting. GitHub page the author mentions that a Raspberry Pi shield called the QRPi filter + amplifier is currently in development (white paper). To get idea of it, take a look at Testing qtcsdr: receiving the transmission with an RTL-SDR via attenuator video:
In the end I must say that I am amazed what can be done with such cheap radio hardware (RTL-SDR and Raspberry Pi). rpitx is a radio transmitter for Raspberry Pi (B, B+, PI2, PI3 and PI zero) that transmits RF directly to GPIO. It can handle frequencies from 5 KHz up to 500 MHz. Plug a wire (acts as antenna) on GPIO 18, means Pin 12 of the GPIO header (header P1). The software can accept an I/Q signal as an input, so now a Pi can be used as a general purpose SDR transmitter. Check out Application note on using GNU Radio and csdr with rpitx and Evariste Courjaud, F5OEO: Rpitx : Raspberry Pi SDR transmitter for the masses video:
I am amazed that it can go to this high frequencies and all this can be made with Raspberry Pi with some software magic.