Hands-On IoT Hacking: Rapid7 at DefCon IoT Village, Part 2

Hands-On IoT Hacking: Rapid7 at DefCon IoT Village, Part 2

In our last post, we discussed how we set up Rapid7's hands-on exercise at the Defcon 29 IoT Village. Now, with that foundation laid, we'll get into how to determine whether the header we created is UART.

When trying to determine baud rate for IoT devices, I often just guess. Generally, for typical IoT hardware, the baud rate is going to be one of the following:

9600192003840057600115200

Typically, 115200 and 57600 are the most commonly encountered baud rates on consumer-grade IoT devices. Other settings that need to be made are data bits, stop bits, and parity bits. Typically, these will be set to the following standard defaults, as shown in Figure 5:

Figure 5: Logic 2 Async Serial Decoder Settings

Once all the correct settings have been determined, and if the test point is UART, then the decoder in the Logic 2 application should decode the bit stream and reveal console text data for the device booting up. An example of this is shown in Figure 6:

Figure 6: UART Decode of Channel 1

FTDI UART Setup

Once you've properly determined the header is UART and identified transmit, receive, and ground pins, you can next hook up a USB to UART FTDI and start analyzing and hacking on the IoT device. During the IoT Village exercise, we used a Shikra for UART connection. Unfortunately, the Shikra appears to no longer be available, but any USB to UART FTDI device supporting 3.3vdc can be used for this exercise. However, I do recommend purchasing a multi-voltage FTDI device if possible. It's common to encounter IoT devices that require either 1.8, 3.3, or 5 vdc, so having a product that can support these voltage levels is ..

Support the originator by clicking the read the rest link below.